Ocular Anatomy Flashcards

Question

Deep layer of the palpebral conjunctiva stroma

Answer 1

connects the conjunctiva to the underlying internal structures . Contains accessory lacrimal glands, nerves and blood vessels of eyelids

Answer 2

dense CT of the tarsal plate.

Answer 3

enormous sebaceous glands within the tarsal plate that open along the lid margins just posterior to the eyelash follicles. Produce the anterior lipid layer of the tears. 25 glands in the upper lid and 20 in the lower lid.

Answer 4

modified sebaceous glands associated with eyelash follicles (usually 2 zeiss glands per eyelash). They lubricate the eyelashes to prevent them from becoming brittle.

Answer 5

modified apocrine glands located near the lid margin. They empty their contents onto eyelash follicles, zeiss glands, and the lid margin.

Answer 6

accessory lacrimal glands that are located in the fornices of the conjunctiva. They are considered merocrine glands and secrete fluids of the same composition as the main lacrimal gland. Krause in crease

Answer 7

accessory lacrimal gland that are larger and less numerous than the glands of Krause. The yare located predominately in the tarsal conjunctiva.

Answer 8

Meibomian and zeiss | Whole cell

Answer 9

Moll and goblet cells | Portion of plasma membrane

Answer 10

Accessory lacrimal glands | Cell substance

Answer 11

zygomatic branch of the facial nerve; innervated the orbicularis oculi

Answer 12

sympathetic nervous system innervated the muscle or muller

Answer 13

Trigeminal | innervated by the frontal (supraorbital and Supratrochlear branches) and lacrimal branches of V1 (ophthalmic nerve)

Answer 14

innervated by the infraorbital and zygomaticofacial branches of V2 (maxillary)

Answer 15

Branches from the nasociliary nerves of V1 and innervated the medial aspect of the upper and lower eyelids

Answer 16

Lateral and medial palpebral arteries | -marginal and peripheral palpebral arcades

Answer 17

provide circulation to the bulbar conjunctiva and the CB; this explains why patients with uveitis can experience circumlimbal injection and decreased aqueous humor production in the involved eye.

Answer 18

facial artery branches off of the external carotid and provides circulation to the superficial areas of the eyelid

Answer 19

* lymphatic vessels are found in the conjunctiva and parallel the veins. * Lateral lymphatics: drain into the parotid (preauricular) lymph nodes * Medial lymphatics: drain into the submandibular lymph nodes.

Answer 20

viral conjunctivitis (classic for EKC), chlamydial conjunctivitis, and dacryoadenitis (among others). Gonococcal conjunctivitis is the only type of bacterial conjunctivitis that presents with preauricular lymphadenopathy. Parinaud’s oculoglandular syndrome presences with significant preauricular AND submandibular lymphadenopathy.

Answer 21

the main elevators of the eyebrows and forehead. Fibers run vertically to raise the eyebrows in a look of surprise or attention ‣ Originate high on the scalp and inserts near the superior orbital rim ‣ The fontalis muscle ‣ is often used to compensate for a ptosis

Answer 22

medial depressor of the eyebrow. Fibers run obliquely and move the medial edge of the eyebrow down and inward for a look of concentration or sorrow ‣ Originates on frontal bone and inserts into the skin above the media leyebrows ‣ Produces the vertical wrinkles of the forehead as an element of facial expression ‣ Helps to reduce sun glare Concentration and corner

Answer 23

medial depressor of the eyebrow. Pulls skin between the eyebrows down for an appearance of menace or aggression ‣ Originates on the nasal bone (bridge of the nose) and inserts on the frontalis muscle between the eyebrows on each side of the midline, ‣ Produces horizontal furrows across the bridge of the nose.

Answer 24

Orbicularis oculi

Answer 25

in a fosses on the temporal side of the frontal bone. Divided into orbital and palpebral portions by the tendon of the superior levator muscle. It is an exocrine gland that releases its products vis merocrine secretion

Answer 26

◦ Supplied by the glandular branches of the lacrimal artery and drained by the lacrimal vein. It contains the ONLY LYMPHATIC vessels of the orbit (drains into the parotid lymph nodes)

Answer 27

parasympathetic innervation from the lacrimal nerve of the pterygopalatine ganglion of CN VII. Parasympathetic stimulation causes secretion of the aqueous layer of the tears. ◦ Some sympathetic nerve fibers also follow the lacrimal artery to innervate the lacrimal gland

Answer 28

infection or inflammation of the lacrimal gland and can result in acute swelling and discomfort in the upper lateral eyelid. Main causes are staph and sarcoidosis, and mono.

Answer 29

lacrimal puncta, canaliculi, lacrimal sac, and the nasolacrimal duct

Answer 30

◦ Located within a ring of CT called the lacrimal papilla. Each puncta in the upper and lower lid drains into a canaliculua ◦ The lacrimal papilla is responsible for keeping the puncta open

Answer 31

◦ 10mm long tube lined with stratified and pseudostratified epithelium that connects each puncta to the lacrimal sac ◦ Each tube initally runs vertically 2mm, then travels medically 8mm before joining together to form the common canaliculis that enters the lacrimal sac. The angle at which the common canaliculis enters the sac prevents backflow ◦ The muscle or Horner (part of the orbicularis oculi) surrounds the canaliculis. Contracts to assist in tear drainage.

Answer 32

lies within a fossa in the medial orbital wall formed by the posterior lacrimal crest bone and the anterior lacrimal crest of the maxillary bone. ◦ 10-12mm long ◦ Lined with double epithelium with microvilli and goblet cells. ◦ The orbital septum is posterior to the lacrimal sac, making it more susceptible to infections. The check ligament of the medial rectus is also posterior to the lacrimal sac ◦ The medial palpebral ligament (from the medial upper and lower tarsal plate) divides into two sections that attaches in front of and behind the sac, straddling it. ◦ The muscle or Horner also surrounds the lacrimal sac, dividing it into upper and lower sections

Answer 33

an infection of the lacrimal sac. It usually occurs as a result of nasolacrimal duct obstruction

Answer 34

* Child: problem with valve of hasner * Adult: age related stenosis (involutional) * Will have unilateral epiphora

Answer 35

``` • I: fluoroscene and five minutes ◦ All NaFL should be gone in 5m ◦ If not, move onto II • II: saline into canaliculi ◦ Push through, if rock rock solid ◦ Make patient choke=broken blockage ◦ Saves from DCR ```

Answer 36

◦ Travels within the nasolacrimal canal that is formed by the posterior lacrimal crest of the maxillary bone and the inferior concha and lies adjacent to the maxillary sinus. It is 15mm Lon and is lined with double epithelium, microvilli, goblet cells. Terminates in the inferior meatus of the nasal cavity

Answer 37

◦ Located at the end of the nasolacrimal duct. It prevents back flow of nasal fluids into the lacrimal drainage system

Answer 38

globe of the eye, the EOMs, the optic nerve, and other smaller nerves, connective tissue, and adipose tissue

Answer 39

Thyroid related ophthalmopathy

Answer 40

located WITHIN the muscle cone of the four recti muscles and serves to separate them from the optic nerve

Answer 41

located OUTSIDE the muscle cone between the EOMs and the walls of the orbit.

Answer 42

Denser blood supply and nerve supply | Faster movements and more fatigue resistant due to unique combo of red and white fibers

Answer 43

‣ Originates from the common tendionous ring (annulus of Zinn) ‣ 7.7mm from the limbus ‣ The sheath covering the SR is connected to the sheath of the superior levator muscle and the CT of the superior conjunctival fornix. These connections ensure that the lid is raised when the eye is in upgaze.

Answer 44

‣ Originates from the common tendinous ring ‣ 6.5mm from the limbus ‣ IR sheath combines with the IO sheath to form the supensory ligament of Lockwood. It attaches to the inferior tarsal plate and extends from the zygomatic bone of the lateral wall to the lacrimal bone of the medial wall to provide support for the globe.

Answer 45

‣ originates from the common tendinous ring | ‣ 6.9mm from the limbus

Answer 46

‣ Originates from the common tendinous ring | ‣ 5.5mm from the limbus

Answer 47

‣ Originates on the lesser wing of the sphenoid bone and the CTR ‣ Travels anteriorly before looping through the trochlea to insert on the superior lateral globe behind the equator ‣ Trochlea is considered the physiologic origin of the SO because it changes its direction of action

Answer 48

The recti muscle insertions on the globe form the spiral of Tillaux, with the SR inserting furthest away from the MR inserting closest to the limbus

Answer 49

‣ Originates ANTERIORLY at the maxillary bone. It inserts on the inferior lateral globe behind the equator

Answer 50

‣ All EOM tendons pierce tenon’s capsule, which sends a “sleeve” of CT with the tendons for a short distance before they merge with the sclera.

Answer 51

Abduction | No secondary or tertiary

Answer 52

Adduction | No secondary or tertiary

Answer 53

Elevation Intorsion Adduction

Answer 54

Depression Extrusion Adduction

Answer 55

Intorsion Depression Abduction

Answer 56

Extorsion Elevation Abduction

Answer 57

two muscular branches from the ophthalmic artery ◦ Superior lateral branch supplies the SR, LR, and SO ◦ Inferior medial branch supplies the IR, MR, and IO ◦ The lacrimal, supraorbital, and infraorbital arteries may provide a minor blood supply to the EOMs

Answer 58

SR=superior CN III IR, IO, MR=inferior CN III LR=CN VI SO=CN IV

Answer 59

◦ Composed of dense CT that covers the bones of the orbit. It provides support to the blood vessels within the orbit and serves as a point of attachment for muscles, tendons, and ligaments. It is continuous with the periosteum of the skull and bones of the face. ‣ Within the optic canal, it is continuous with the dura surrounding the brain and the ON ‣ A portion covers the lacrimal gland, the lacrimal sac, and contributes to the lining of the nasolacrimal canal ‣ The anterior orbital fascia forms the orbital septum within the upper and lower eyelids.

Answer 60

single bone whose middle portion (the body) form the base of the cranium. The optic canal in each eye is located just lateral to the center of the sphenoid body

Answer 61

depression in the body of the sphenoid bone that houses the pituitary gland. Remember, the optic chiasm lies superior to the pituitary gland. A pituitary gland tumor can damage the nasal retinal fibers from each eye that run just superior to the pituitary gland as they cross in the optic chiasm, causing a bitemporal hemianopsia.

Answer 62

projects anteriorly to connect with the frontal bone to form the roof of the orbit. “Front less”=frontal bone and lesser wing of sphenoid form the roof of the orbit. • Things that arise from the lesser wing: levator, SO, optic nerve • The optic canal is located within the lesser wing and contains the optic nerve and the ophthalmic artery

Answer 63

projects laterally to connect with the zygomatic bone to form the lateral wall of the orbit. “The great Z”=the greater wing of the sphenoid and the zygomatic to form the lateral wall of the orbit. The greater wing of the sphenoid contains 3 important foramina: • Rotundum: V2 (rotwondum) • Ovale: V3 (ov3ale) • Spinosum: middle meninges artery (important in cases of truama)

Answer 64

◦ Opening between the greater and the lesser wing O.D. the sphenoid bone ‣ Located between the posterior lateral wal land the superior wall ‣ The cavernous sinus lies just posterior to the SOF and travels on the side of the sphenoid body ‣ Anterior to the SOF is the CTR

Answer 65

circular band of CT that lies just anterior to the superior orbital fissure (SOF) and serves as the origin of the recti muscles. The CTR is AKA annulus of Zinn.

Answer 66

‣ Nasociliary nerve (V1), oculomotor nerve, and abducens nerve (NOA nerves) ‣ The sympathetic root of the ciliary ganglion travels with the nasociliary nerve as it passes through the SOF and CTR

Answer 67

‣ Superior ophthalmic vein ‣ Frontal nerve ‣ Lacrimal nerve ‣ Trochlear nerve

Answer 68

Inferior ophthalmic vein

Answer 69

ON and ophthalmic artery

Answer 70

ICA and sympathetic plexus

Answer 71

supraorbital nerve (V1) and vessels (supraorbital artery and vein)

Answer 72

infraorbital nerve (V2) and vessels (infraorbital artery and vein)

Answer 73

inferior alveolar nerve and vessel

Answer 74

Facial nerve

Answer 75

Frontal bone | Lesser wing of sphenoid

Answer 76

the anterolateral portion of the orbital roof within a fossa of the frontal bone

Answer 77

Maxillary Palatine Zygomatic

Answer 78

The postero-medial portion of the floor

Answer 79

• The infraorbital nerve runs along the infraorbital groove of the floor before exiting the orbit through the infraorbital foramen. ◦ Loss of sensation in cheek if damaged

Answer 80

``` SMEL Body of sphenoid Maxillary Ethmoid Lacrimal ``` Thinnest and smallest

Answer 81

also known as the lamina papyracea. An infection in the sinus cavity can often spread to the orbit through the very thin lamina papyracea, resulting in orbital cellulitis.

Answer 82

Greater wing of sphenoid Zygomatic The great Z

Answer 83

Facial Maxillary Superficial temporal

Answer 84

* Branches at the angle of the mandible and travels across the mandible and cheek toward the medial canthus of the eye * The angular artery: terminal branch of the facial artery that communicates with the dorsal nasal artery and supplies the medial canthus

Answer 85

* Terminal branch of the ECA that begins just anterior to the ear in the parotid gland * The infraorbital branch of the maxillary artery enters the orbit through the inferior orbital fissure and supplies the IR and IO. * It exits the orbit through the infraorbital foramen and supplies the lower eye lid and the lacrimal sac before joining the angular artery and the dorsal nasal artery

Answer 86

• The second terminal branch of the ECA that arises within the parotid gland ◦ It has 3 branches that supply the superficial skin, muscles, and soft tissue around the face and orbit ◦ The superficial temporal artery communicates with branches from the ophthalmic artery

Answer 87

inflammation of large and medium sized vessels that supply the head. Damage to the PCA (circle of zinn) leads to suffocation and irreversible damage of the ONH (AAION) and results in significant loss of vision. This inflammatory process can quickly spread to the fellow eye if not promptly treated with oral corticosteroids and is thus considered an ocular emergency.

Answer 88

``` OPAM Ophthalmic Posterior communicating Anterior cerebral Medial cerebral ```

Answer 89

‣ Branches from the ICA and ECA anastomose to provide for certain ocular structures. For example, the superficial temporal artery has a connection with the supraorbital artery; if the ophthalmic artery is obstructed and cannot provide blood flow to the orbit, this connection can temporarily provide a low level of circulation

Answer 90

◦ ICA enters the skull through the patrols portion of the temporal bone and travels directly into the cavernous sinus ◦ CN VI travels alongside the ICA as it course through the cavernous sinus. CN III is lateral and CN II is medial to the ICA just before it exits the sinus. ◦ The ophthalmic artery is the first branch of the ICA as it approaches the orbit

Answer 91

Within the optic nerve sheath • After leaving the sheath, the ophthalmic artery travels near the medial wall of the orbit (along with the nasociliary nerve) between the SO and MR

Answer 92

``` CL MS LSE CRA Lacrimal artery Muscular artery Short posterior ciliary arteries Long posterior ciliary arteries Supraorbital artery Ethmoid artery ```

Answer 93

‣ First branch of the opthalmic artery. It travels within the optic nerve and supplies the nerve and surrounding pia mater via collateral branches. it enters the optic disc slightly nasal to center and divides into multiple superior and inferior branches. The CRA supplies the inner 2/3 of the retina

Answer 94

Ophthalmic branch ‣ Travels along the lateral wall of the orbit and supplies the LR and the lacrimal gland. It terminates as branches of the lateral palpebral artery that supplies the lateral inferior and superior lids • The lateral palpebral arteries anastomose with the medial palpebral arteries to form the palpebral arcades of the eyelids

Answer 95

Branch of ophthalmic ‣ Provides blood to EOMs via two branches • Superior lateral muscular artery: LR, SR, SO • Inferior medial muscular artery: MR, IR, and IO

Answer 96

• Branches of the muscular artery that supply the four recti muscles collectively from the anterior ciliary arteries, a vascular network that combines with the long posterior ciliary arteries to form the major arterial circle of the iris

Answer 97

Branch of ophthalmic ‣ One or two large branches enter the eye one both sides of the optic nerve before quickly branching 10-20 times within the choroidal stroma to form the arterial network (the circle of Zinn) that supplies the superficial optic nerve head. The SPCAs also supply the posterior choroid, including the macula

Answer 98

Circle of zinn | SPCAs

Answer 99

Branch of ophthalmic ‣ Two arteries enter the eye one each side of the optic nerve and travel between the sclera and the choroid. They join the SPCAs to form a network of blood supply to the choroid • LPCAs provide for the anterior choroid before traveling to the CB to join with the anterior ciliary arteries to form the major arterial circle of the iris • Overall, the LPCAs supply the iris, CB, and anteiror region of the choroid

Answer 100

In the CB It contains fenestrated capillaries that allow plasma to leak out, which ultimately contributes to aqueous humor formation.

Answer 101

Branch of ophthalmic | SR, SO, Levator, scalp and forehead

Answer 102

Ophthalmic branch | sphenoid, frontal, and ethmoid sinuses

Answer 103

OPL INL NFL

Answer 104

Terminal branch of the ophthalmic artery | skin of forehead and scalp, as well as muscles of forehead

Answer 105

Terminal branch of ophthalmic artery supplies the lacrimal sac and then travels along the side of the nose to join the angular artery (front he facial branch of the ECA) ‣ The dorsal nasal artery branches into the medial palpebral arteries that supply the medial superior and inferior eyelids. Remember, these arteries join with the lateral palpebral arteries to form the palpebral arcades

Answer 106

ICA or the ophthalmic artery

Answer 107

They do not contain valves

Answer 108

DOES NOT correspond to the arterial supply

Answer 109

drains blood from the inner 6 layers of the retina tha tare supplied by the CRA. It exits the eye through the optic nerve and then enters the cavernous sinus, either directly or after joining the superior ophthalmic vein.

Answer 110

◦ Drain blood from the anteiror structures of the eye including outer portion of the CB, the conjunctiva, and schlemm’s canal. The anterior ciliary veins follow the path of the anterior ciliary arteries across the tendons of the four recti muscles. They drain into the superior and inferior ophthalmic veins

Answer 111

◦ Drain blood from the choroid. Usually one per quadrant. Drains into the superior and inferior ophthalmic veins

Answer 112

◦ Largest vein in the orbit. Responsible for the majority of venous drainage of the eye, receiving blood from the CRV, the superior vortex veins, the muscular veins draining the SR and MR (also receives blood from the anterior ciliary arteries), and the lacrimal vein ◦ Exits the orbit through the SOF and drains into the cavernous sinus

Answer 113

◦ Originates from a diffuse network of veins along the anterior medial orbital floor between the globe and the IR. It receives blood from the muscular veins draining the MR, IR, IO, and LR (which also receives blood from the anterior ciliary veins), the inferior vortex veins, and small veins draining the inferior conjunctiva, lower eyelid and the lacrimal sac. Two branches: ‣ Inferior branch exits the orbit through the inferior orbital fissure and drains into the pterygoid plexus to communicate with the facial veins ‣ Superior branch exits the orbit through the superior fissure and drains the cavernous sinus, either directly or after joining with the superior ophthalmic vein

Answer 114

originates on the forehead and joins the frontal vein near the medial angle of the orbit to form the angular vein. It sends a branch through the supraorbital notch that helps form the SOV ◦ Frontal veins: originates from a venous plexus on the forehead. It communicates with the superficial temporal vein before joining the supraorbital vein at the medial angle of the orbit, forming the angular vein

Answer 115

‣ Originates on the side of the nose and the medial angle of the orbit. It sends a nasofrontal branch into the orbit, which joins the supraorbital branch to form the SOV. The angular vein eventually beceoms the anterior facial veins at the lower margin of the orbit • The anterior facial vein receives blood from a branch of the pterygoid venous plexus, as well as the superior and inferior palpebral veins • It travels from the side of the nose along the masseter until it joins with the posterior facial vein, forming the common facial vein. The common facial vein drains into the internal jugular vein

Answer 116

‣ Arises from several superficial veins that drain the face. It enters the orbit via the infraorbital foramen and travels along the floor of the orbit within the infraorbital groove and canal. The infraorbital vein receives branches from small veins that drain structures of the inferior orbit before emptying into the pterygoid plexus

Answer 117

located with in the infratemporal fossa. It communicates with the anterior facial vein and the cavernous sinus via orbital veins and emissary veins of the cranium. The venous plexus eventually forms the maxillary vein

Answer 118

‣ Originates from the venous plexus on the side of the skull. The frontal branches and parietal branches of the venous plexus join to form the trunk of the superficial temporal vein. It communicates with the frontal, supraorbital, posterior auricular, middle temporal, and occipital veins before joining the maxillary vein within the parotid gland to form the posterior facial vein • The middle temporal vein receives blood from the orbital vein that originates from lateral palpebral venous branches

Answer 119

‣ Aka restromandibular vein; formed by the union of the superficial temporal vein and the maxillary vein within the parotid gland. Divides into anterior and posterior branches • Anterior: unites with the anterior facial vein to form the common facial vein. The common facial vein drains into the internal jugular vein • Posterior: joins with the posterior auricular vein (which communicates with the occipital and superficial temporal veins) to form the external jugular vein)

Answer 120

originates at the posterior vertex of the skull. It may drain directly into the internal jugular vein or join the posterior auricular vein to drain into the external jugular vein

Answer 121

union of the retromandibualr vein and the posterior auricular vein and drains blood from the superficial face

Answer 122

continuation of the sigmoid sinus and drains blood from the common facial, occipital, lingual, and superior and medial thyroid veins.

Answer 123

Dural sinuses of the head

Answer 124

located between the sphenoid and temporal bones, the cavernous sinus begins just posterior to the inferior medial region of the SOF of each orbit and extends to the petrous portion of the temporal bone. The sphenoid sinus is inferior and the optic chiasm is superior to the cavernous sinus

Answer 125

superior and inferior ophthalmic veins as well as the superficial middle cerebral vein and inferior cerebral veins

Answer 126

into the superior and inferior pterosaurs sinuses, which ultimately drain into the internal jugular vein to carry blood to the heart. may also communicate with the pterygoid plexus thorough a network of emissary vein that exit the skull through the foramen ovale and foramen lacerum

Answer 127

‣ The area of the face from the corners of the mouth to the bridge of the nose is sometimes called the “triangle of death.” Infections in this area can gain access to the brain through the cavernous sinus because of venous communication between the facial vein and the ophthalmic veins.

Answer 128

3,4,6 V1, V2 ICA Postganglionic symp and preganglionic parasympathetic fibers

Answer 129

• Note that V3 (mandibular branch of the trigeminal nerve), CN VII, and preganglionic parasympathetic fibers that travel with CN VII (lacrimation) do not travel within the cavernous sinus. Facial muscles control (including eyelid closure) and lacrimation will therefore remain intact in patients with cavernous sinus disease.

Answer 130

ICA | most likely to be affected by an ICA aneurysm

Answer 131

inflammation of the SOF and/or cavernous sinus that often affects CN 3,4,5,6, resulting in painful external ophthlamoplegia and diplopia

Answer 132

occurs because of an abnormal communication between the arterial and venous blood supplies within the cavernous sinus. It is assocaited with a painful red eye, orbital bruit, and pulsatile proptosis

Answer 133

◦ Drains blood from the inferior cerebral veins and some cerebellar veins. It communicates with the cavernous sinus and the transverse sinus

Answer 134

◦ Originates from the posterior inferior portion of the cavernous sinus. It receives blood from the internal auditory veins as well as veins from the brainstem and cerebellum. The inferior petrosal sinus exits the skull through the jugular foramen and drains into the internal jugular vein

Answer 135

◦ Located within the superior flax cerebri (strong folds of dura mater that separate the right and left hemispheres of the brain) on the upper petrous portion of the temporal bone. The superior sagittal sinus drains blood from the superior cerebral veins. It travels posteriorly to the internal occipital protuberance, where it drains into the right transverse sinus

Answer 136

◦ Travels within the inferior portion of the fall cerebri between the occipital bone and the petrous portion of the temporal bone. It receives blood from the inferior cerebral veins. The inferior sagittal sinus travels posteriorly to join the great cerebral vein to form the straight sinus.

Answer 137

◦ Originates at the junction of the fall cerebri and the tentorium. It drains blood from the superior cerebellar veins before draining into the left transverse sinus

Answer 138

Originates at the margin of the foramen magnum and travels within the fall cerebri along the occipital bone, it receives blood from the vertebral veins before draining the left transverse vein

Answer 139

◦ Travel on the surface of the tentorium along the occipital bone and the petrous portion of the temporal bone. It receives blood from the superior petrosal sinus, inferior cerebral veins, and inferior cerebellar veins. They eventually travel inferiorly to form the sigmoid sinuses ‣ Sigmoid sinus receives the inferior petrosal sinus (which communicates with the cavernous sinus). It exits the skull through the jugular foramen and becomes the internal jugular vein

Answer 140

meeting point for the superior sagittal, straight, occipital, and transverse sinuses and is located on the internal occipital protuberance of the occipital bone.

Answer 141

• transmits and refracts light and serves a barrier against pathogen and edema

Answer 142

• the air/tear film interface has the largest refractive index difference between two layers and thus serves as the main refracting element, contributing to 44D of the refractive power of the cornea. ◦ Air n=1.00, tear film n=1.336, cornea n=1.376 ◦ The tear film/cornea interface contributes 5D and the cornea/aqueous humor interface contributes -6.00D to the total refractive power of the cornea

Answer 143

Steeper in the vertical meridian

Answer 144

Steeper in the horizontal meridian

Answer 145

‣ Astigmatism shifts towards ATR as the crystalline lens ages. A loss of lid tension may also contribute in flattening of the vertical meridian of the cornea, contributing to the increase in ATR astigmatism

Answer 146

◦ Stratified squamous non keratinized epithelium. Contains 5-6 cell layers that are approximately 52um thick. There are four difference layers of the epithelium

Answer 147

Connect BM to things

Answer 148

composed of 2 layers of non keratinized squamous cells. The plasma membrane of these cells secretes a glycocalyx and contains microvilli and microplicae to increase the surface area and enhance the stability of the tear film. ‣ Zonula occludens and desmosomes form a tight barrier between cells to impede the intercellular movements of particles. This is the ONLY CELL LAYER WITHIN THE CORNEA THAT CONTAINS ZONULA OCCLUDENS

Answer 149

Surface layer of the epithelium

Answer 150

2-3 cell layers joined by desmosomes to each other and to surrounding layers

Answer 151

the ONLY MITOTIC LAYER in the corneal epithelium; composed of 1 layer of columnar cells. The basal layer of the epithelium secretes its own basement membrane (the basal lamina). The BM attaches to the underlying bowmans layer via hemidesmosomes that penetrate bowmans and attach to the extracellular matrix of the corneal stroma. ‣ Reduplication of the BM occurs with age. By 60, the BM in normal eyes doubles in thickness.

Answer 152

``` Basal lamina (secreted by epithelial cells) Reticular lamina (secreted by underlying stromal cells) ```

Answer 153

Poor hemidesmosome formation (trauma) Epithelial BM dystrophies Age related thickening of the BM

Answer 154

originate from the palisades of Vogt, a 0.5-1.0mm band around the limbus at the same level as the basal layer, allowing for an easy transition as stem cells migrate circumferentially to become basal cells. Remember, stem cells become basal cells, and basal cells produce wing wells that migrate anteriorly to eventually become the surface layer of the epithelium

Answer 155

has been shown to contribute to poor corneal epithelial maintenance in individuals with aniridia. SJS, and alkali corneal burns.

Answer 156

◦ An acellular layer primarily composed of random type 1 and 5 collagen fibrils . It is a transition layer from the epithelium into the stroma; it is not a basement membrane ‣ Most say Bowman’s is produced prenatal by anterior stromal fibroblasts, although there are other sources that’s say it is produced prenatally by corneal epithelial cells. It is 8-14 microns thick ‣ Tough layer that is resistant to damage or injury; however, if damage occurs, bowmans cannot regenerate, resulting in the formation of a scar. ‣ Bowmans may play a role in maintaining the correct curvature of the cornea

Answer 157

* Band keratopathy: calcium deposits (Swiss cheese pattern) within bowmans * Pterygia: Detroit bowmans layers as they progress onto the cornea * Crocodile shagreen: bilateral gray white polygonal stromal opacities that may involve bowmans layer * Reid-buckler dystrophy: rare corneal epithelial dystrophy that appears as early in life and is secondary to damage to bowmans layer * Keratoconnus: inital damage occurs in bowmans layer. Remember that advanced keratoconnus may result in hydrops due to damage to descemets membrane * Refractive surgery: the flap created during LASIK consists of epithelium AND bowmans layer; PRK involves the application of laser THROUGH bowmans layer, resulting in post op corneal haze.

Answer 158

OI | Ehlers danlos

Answer 159

450um thick. Dense, irregular CT composed of keratocytes (fibroblasts), collagen fibrils, ground substance, and water (75-80% of the stroma)

Answer 160

Stroma of the corneal stroma | fibroblasts of the cornea that produce collage fibrils and the extracellular matrix

Answer 161

In the stroma the stroma contains about 200-300 layers of uniformly spaced 30nm lamellae (comprised mainly of type I collagen) that run parallel to the corneal curface. Uniform spacing of collagen lamellae is essential for maintaining corneal transparency

Answer 162

* The anteiror 1/3 of the stroma has a higher incidence of cross linking between collagen fibers compared to the posterior 2/3 of the stroma, creating more rigidity and helping to maintain corneal curvature * The posterior 2/3 of the stroma is more organized and consists very uniformly spaced lamellae that are larger and have less branches and less cross linking compared to the anterior 1/3 of the stroma, factors that result in a higher incidence of corneal edema in the posterior cornea.

Answer 163

serve as a filler between the collagen fibrils and keratocytes. Contains GAGs that attract water, contributing to the precise spacing between collagen lamellae that is essential for corneal transparency. • Keratin sulfate: predominate GAG within the cornea

Answer 164

Keratin Sulfate

Answer 165

``` Avascular Obtains nutrients though -diffusion from aqueous humor -limbal conjunctiva and episcleral cap networks -palpebral conjunctival networks ```

Answer 166

Palpebral conjunctiva

Answer 167

defense response to oxygen deprivation. The new vessels arise from endothelial cells of the limbal capillary network in response to stroking s and growth factors (including VEGF)

Answer 168

Epithelium | Descemets

Answer 169

DM | Descemets

Answer 170

Endortheloiyum

Answer 171

• responsible for pain sensation and for proper wound healing. V1 divides into the nasociliary nerve, which then divides into the long and short posterior ciliary nerves that directly innervate the cornea.

Answer 172

branch directly from the nasociliary nerve. SPCNs are formed after the nasociliary nerve travels through the ciliary ganglion. The LOCNs and SPCNs form a myelinated network of 60-80 nerves that enter the mid stroma. ◦ After traveling 2-4mm inside the stroma, the corneal nerves lose their myelin sheath as they penetrate through bowmans layer to enter the epithelium. These nerves are nor highly snesitive naked nerves packed with nocirecptors that mediate pain.

Answer 173

characterized by poor corneal sensitivity and wound healing and is secondary to damage to V1 of the trigeminal nerve (herpes zoster, herpes simplex, CVA, DM) ‣ V1 tells stem cells to becom basal • Cells shed, stimulate new growth • Detect pain • No more signaling to produce more cells and loss of sensation. “Big ulcer, no pain”

Answer 174

◦ Epithelium: referred to as he intraepithelial plexus ◦ Anteiror stroma/Bowmans layer: referred to as the subepithelial plexus ◦ Mid stroma: stromal plexus

Answer 175

posterior stroma, Descemets membrane, or corneal endothelium. Remember, the corneal nerves enter at the level of mid stroma and travel anterior to form there.

Answer 176

◦ Protection of the soft tissues of the eyelid and orbit ◦ Allows extensive movement of the eye without damaging soft tissues ◦ Serves as a source of antimicrobial and other immunological agents ◦ Produces the mucin layer of the tears

Answer 177

Stratified non keratinized epithelial layer Submucosa layer

Answer 178

composed of cuboidal/columnar cells in the palpebral conjunctiva that become squamous cells in the bulbar conjunctiva. The superficial cells contain melanin granules, microvilli, and goblet cells.

Answer 179

loose CT layer that is separated into two layers ‣ Outer lymphoid layer: contains IgA, macrophages, mast cells, lymphocytes, PMN leukocytes, eosinophils, and langerhans cells ‣ Deep fibrous layer: contains collagen fibrils, fibroblasts, blood vessels, lymphatic vessels, nerves, and accessory lacrimal glands. In general, this layer is loosely attaches to underlying structures

Answer 180

◦ Covers the eyelid marking, tarsal plate, and the fornices

Answer 181

lines the eyelid margins and is composed of stratified columnar epithelial cells that become continuous with the epithelium of the skin at the mucocutaneous junction of the lid. The underlying submucosa is very thin with only a deep fibrous layer

Answer 182

lines the tarsal plates and is composed of stratified columnar epithelium. The submucosa is thicker and contains the outer lymphoid and deep fibrous layers, which contains the accessory lacrimal glands and is strongly attached to the tarsal plate.

Answer 183

lines the fornices. The deep fibrous layer contains the accessory lacrimal gland and mullers muscle (in the upper fornix). The EOM fascia attach to the forniceal conjunctiva, moveing the conjunctiva in conjunction with the eye to avoid compression of blood vessles and nerves within the submucosa.

Answer 184

◦ Thin, translucent membrane that covers the sclera. Composed of stratified squamous cells that become continuous with the corneal epithelium at the limbus. The submucosa is loosely attached to underlying tenons capsule until appx 3mm from the cornea when it fuses with the end of tenon capsule, episclera, and sclera.

Answer 185

Caruncle Inferior nasal fornices Temporal bulbar conjunctiva

Answer 186

1-2mm zone that encircles the cornea and serves as the junction between the conjunctiva, sclera, and cornea ‣ The limbus provides nutrients for neighboring structures ‣ The limbus provides a passageway for aqueous humor drainage within the eye ‣ Supplied by blood from capillary loops of the conjunctival and epi scleral vessels

Answer 187

‣ The limbal epithelium contains 10 cell layers compared to the 5 cell layers of the corneal epithelium ‣ Bowmans layer and descemets membrane end at the limbus. Remember that descemets membrane beceoms schwalbes line in the anterior chamber angle ‣ The conjunctival stroma, episclera, and tenon’s capsule begin at the limbus

Answer 188

spoke like projections of limbal conjunctiva that extend 4mm from the edge of the cornea. The limbal epithelium is the source of stem cells that migrate to the basal layer of the cornea

Answer 189

Scleritis/adenovirus=diffuse injection | Uveitits-circumlimbal

Answer 190

composed of stratified squamous bulbar conjunctiva that folds at the medial canthus, providing slack in the conjunctiva during lateral eye movements. It also serves as the floor of the lacrimal lake

Answer 191

a hybrid of conjunctiva and skin that contains sebaceous glands, sweat glands, and goblet cells and is located on the medial side of the plica semilunaris. Function unknown. Likely the source for the collection of debris that is present in the healthy eye upon wakening

Answer 192

marginal and peripheral palpebral arcades.

Answer 193

peripheral palpebral arcades. Anterior bulbar conjunctiva is supplied by the anterior ciliary arteries. The peripheral palpebral arcades combine with the anterior ciliary arteries at the posterior bulbar conjunctiva

Answer 194

The antieror ciliary veins

Answer 195

• lateral lymphatic vessels of the bulbar and palpebral conjunctiva drain into the parotid lymph nodes. Medial lymphatic vessels drain into the submandibular lymph nodes

Answer 196

innervated by the long posterior ciliary nerves (from the nasociliary nerve of V1). The superior palpebral conjunctiva is innervated by the frontal and lacrimal nerves of V1; the inferior palpebral conjunctiva is innervated by the lacrimal nerve of V1 and the infraorbital nerve of V2.

Answer 197

20D (1/3 of the total)

Answer 198

posterior lens surface is attached to the anterior vitreous face by the ring shaped hyaloid capsular ligament. The potential space between the posterior pole of the lens and the anterior vitreous within this ring is known as the retrolental space of Berger.

Answer 199

peripheral flattening and a gradient index of refraction in the lens helps to reduce spherical aberration

Answer 200

transparent basement membrane that surrounds the entire lens and is secreted by the anterior lens epithelium. It is thinnest at the posterior pole and thickest at the anterior pole of the lens (and is thickest BM in the entire body). It is primarily composed of type 4 collagen fibers and GAGs ‣ The lens capsule serves as a barrier against large molecules entering the lens ‣ The lens zonules, which maintain the position of the lens within the posterior chamber, extend from the non pigmented ciliary epithelium and insert into the anterior capsule of the lens

Answer 201

composed of a single layer of cuboidal epithelial cells adjacent to the anterior lens capsule. There is NO posterior lens epithelium in the adult lens, as it was used to form the primary lens fibers during embrological development. Lens epithelial cells are joined with maculae occludens and gap junctions. They serves as the main site of lens metabolism ‣ The pre-equatorial region of the lens (just anterior to the lens equator and known as the germinal zone) containes mitotic epithelial cells that become secondary lens fibers. The production of new lens fibers is continuous throughout life.

Answer 202

composed of 65-70% water ‣ 80-90% of lens proteins are water soluble alpha, beta, and gamma crystallins that are tightly packed within the cytoplasm of lens fiber cells.

Answer 203

• UV exposure and oxidation can cause structural damage to lens fibers. Alpha crystallins act as molecular chaperones by helping beta and gamma crystallins recover from injuries, thus preventing degradation of lens fibers and loss of lens transparency

Answer 204

Molecular chaperones by helping beta and gamma crystallins recover from injuries

Answer 205

varies throughout the lens, creating a gradient index of refraction that is higher in the nucleus (n=1.41) compared to the anterior lens. Remember that aqueous and vitreous humors have an index of refraction of 1.336

Answer 206

by BM of the NPCE in the pars plana and pars plica RA

Answer 207

microfibrils that contain fibrillin and extracellular matrix but NO true elastic fibers

Answer 208

directly to the lens capsule in the pre and post equatorial regions of the lens. Relatively few primary lens zonules attach directly to the lens equator.

Answer 209

connect primary lens zonules to one another or to the NPCE of the pars plana

Answer 210

connect the primary lens zonules to the valleys between the ciliary processes of the pars plicata

Answer 211

``` Adult Juvenile Fetal (Y sutures) Embryonic Fetal (Y) Juvenile Adult ```

Answer 212

Embryonic | ALL others are from anterior

Answer 213

* forms the posterior 5/6 of the protective CT coat of the eye and helps to maintain the shape of the globe * Point of attachment for the EOMs * Mean radius of curvature=11.5mm * Thickest area is 1.0mm at the posterior pole * Thinnest area is 0.3mm under the recti tendon insertions. This is clinically relevant during strab surgery * Weakest area=lamina cribrosa * Considered avascular * Minimally innervated: LPCNs and SPCNs

Answer 214

loose CT that contains capillary network (from the anterior ciliary arteries) that surrounds the cornea. Inflammation of the CB or iris (iritis) will cause dilation of the anterior ciliary arteries. Leading to the characteristics ciliary flush (circumlimbal injection)

Answer 215

In the anterior conjunctiva and the episclera

Answer 216

thick, dense, avasular VT that is continuous with the corneal stroma. Composed of irregular collagen bundles that provide strength but NO transparency. Contains similar ground substance to corneal stroma

Answer 217

‣ The episclera is composed of LOOSE CT and is HIGHLY vascular. The sclera proper is composed of DENSE CT and is relatively AVASCULAR

Answer 218

the innermost layer of the sclera adjacent to the choroid that contains elastin fibers and numerous melanocytes

Answer 219

the sclera commonly has a blue tint because the underlying uveal pigmentation is visible through the thinner sclera. Osteogenesis imperfecta or Ehlers-Danlos syndrome are also assocaited with a blue sclera

Answer 220

often becomes yellow as lipids become trapped in the dense irregular CT over time. A yellow scleral may signify liver disease

Answer 221

thin transparent layer of CT that covers the episclera. It begins 2mm posterior to the limbus and extends posteriorly to encircle the rest of the globe, separating it from the surrounding orbital adipose tissue ◦ Tenons capsule fuses wtih the episclera and th conjunctival submucosa layer ◦ It is perforated posterolaterally by the optic nerve, ciliary vessels and nerves, and the tendons of the 4 recti muscles

Answer 222

conjunctival epithelium, conjunctival stroma, tenons capsule, episclera, sclera proper, and lamina fusca

Answer 223

area occupied by the cornea (11.7mm in diameter)

Answer 224

area wher ethe optic nerve enters the eye. The optic nerve is supported by the lamina cribrosa, which is composed of scleral collagen and elastin fibers that associated with the axon bundles and astrocytes within the optic nerve

Answer 225

‣ The deep and intrasceral venous plexi travel through the sclera to connect with the ciliary vein within the CB ‣ Anteiror ciliary arteries provide blood to most anterior structures of the eyes ‣ Branches from the episcleral arteries travel through the sclera to reach the anterior chamber angle ‣ Aqueous veins of Ascher drain aqueous humor drain from schlemms canal ‣ LCPNs (forming axenfeld nerve loops) provide innervation to most anterior structures of the eye

Answer 226

include vortex veins that drain the choroid

Answer 227

near the optic nerve, include channels for the LPCAs, SPCAs, LPCNs, and SPCNs that travel through the sclera to reach the suprachoroidal space

Answer 228

120-170uL of fluid

Answer 229

corneal endothelium, the TM, schlemms canal, ciliary body, and iris root, and the anteiror iris surface

Answer 230

located within the eye at the corneal scleral junction and contains the site for aqueous filtration. The structures within the internal scleral sulcus, form posterior to anterior, include: ◦ Iris, CB, scleral spur, TM, Schlemms canal, and Schwalbes line

Answer 231

‣ Based on the most posterior structure of the angle that is visible • Grade 4: CB • Grade 0: no structures available ICSTSL 4321

Answer 232

‣ Based on width of the chamber angle compared to the width of the corneal optic section • Grade 4: width of the chamber interval is 1/2 or greater than the width of the corneal optic section

Answer 233

band of collagen and elastin fibers that extends from the inner aspect of the sclera. It is the origin site for the longitudinal ciliary muscle fibers and the TM lamellae

Answer 234

the scleral spur, the lamina cribrosa, and the lamina fusca are the only areas of the sclera that contain elastin

Answer 235

◦ Lines the anterior chamber circumferentially and is the major site for aqueous humor filtration ‣ The TM is triangular in shape, with the base of the triangle abutting the scleral spur and the apex pointing towards the cornea. The juxtacanalicular tissue is the external border of the TM ‣ The inferior portion of the angle typically has the greatest amount of pigment in the TM and is therefore a good starting point when performing gonioscopy

Answer 236

the innermost 1-5 layers of the TM that are located adjacent to the anterior chamber and inward to the scleral spur. It consists of large pores within a network of cords, which are composed of an inner core of collagen, elastin, and ground substance surrounded by a layer of endothelium and BM. The endothelial cells aid in protein synthesis and contain lysosomes for phagocytosis of melanin and debits • Does NOT utilize schlemms canal for outflow (PRESSURE INDEPENDENT); instead, aqueous flows between the ciliary muscle fiber bundles, into the suprachoroidal space, and then through the sclera OR drains through the anterior ciliary veins, cortex veins, or other routes. • The uveoscleral meshwork is a minor site for aqueous humor filtration, accounting for 5-35% of total aquesou humor outflow

Answer 237

Prostaglandins decrease resistance in the uveoscleral meshwork by relaxing the ciliary muscle and causing changes within the extracellular matrix, resulting in an increase in uveoscleral outflow

Answer 238

the outer 8-15 layers of the TM that are located closer to schlemms canal and extend between the scleral spur and the cornea. It contains smaller pores with a network of sheet like fibers similar in composition to the cords of the uveoscleral meshwork. The pores are even smaller within the portion of the TM closest to Schlemms canal and within the juxtacanalicular tissue (JXT)

Answer 239

* The JXT is also referred to as the cribiform layer. It is the outermost portion of the TM and separates the inner wall of schlemms canal from the TM * The JXT is composed of a layer of endothelial cells and extracellular matrix. It is through to contain few microscopic pores and therefore is the site of most resistance to aqueous outflow * In order to penetrate the endothelial tight junctions that line schlemms canal and the endothelial cells that fill the lumen, the aqueous humor must utilize a high to low pressure gradient (IOP must be greater than the episcleral venous pressure)

Answer 240

Uveoscleral Cornealscleral JXT

Answer 241

Pressure idependent

Answer 242

Pressure dependent

Answer 243

Pilo (corneo) PGs (Uveo) A2 agonist (uveo)

Answer 244

◦ Circular venous channel lined by endothelial cells. Serves as the major site of aqueous humor filtration. The inner border is located against the scleral spur and TM. The outer border lies against the sclera near the limbus

Answer 245

lined by endothelial cells that are in contact with the JXT. The endothelial cells contain multiple giant vacuoles that transport aqueous humor across the JXT into schlemms canal

Answer 246

lined with normal endothelial cells (no giant vacuoles) with a thin outer covering of CT. It also contains efferent vessels that drain aqueous humor out of the eye

Answer 247

Schlemm’s canal often contains multiple channels formed by CT septae that increase the surgface area for aqueous filtration. These channels are known as internal collector channels

Answer 248

‣ Short efferents-deep scleral venous plexus-intrascleral venous plexus-episcleral venous plexus ‣ External collector channels -episcleral venous plexus

Answer 249

the anterior ciliary veins-muscular veins-superior/inferior ophthalmic veins-cavernous sinus-superior/inferior petrosal sinus-internal jugular vein-brachiocephalic vein-superior vena cava-right atrium of heart

Answer 250

◦ Collagenous CT that represents the termination of descemets membrane and thus delineates the outer limit of the cornea to the limbus

Answer 251

represents an anteriorly displaced schwalbes line

Answer 252

opening in the iris that is located slightly nasal and inferior to the center. The pupil diameter can range from 1-8mm, but under normal room illumination is an average 3-4mm ◦ The iris at the pupillary margin contains schwalbes contraction furrows that represent variations in the thickness of the posterior pigmented iris epithelium

Answer 253

thickest in the collarette region; thinnest at the iris root

Answer 254

a circular ridge appx 1.5mm from the pupillary margin that served as the site of attachment for the fetal pupillary membrane during embryonic development. The collarette contains remnants of old fetal vessels in addition to active iris vessels. It divides the iris into pupillary and ciliary zones

Answer 255

contains furrows that allow the iris tissue to bunch towards the periphery during dilation. Also contains radial streaks, which are often white in color and represent collagen traveling along the iris vessels

Answer 256

radial streaks are still present but are smaller because the iris blood vessles are smaller towards the pupillary margin

Answer 257

span the collarette into the ciliary and pupillary zones a

Answer 258

located within the ciliary zone of the iris; contains the anteiror border layer and a smaller portion of the iris stroma

Answer 259

located posterior to the anterior iris stromal leaf. It contains most of the iris stroma in the ciliary zone and the anterior border layer and all of the iris stroma in the pupillary zone

Answer 260

rare, bialteral condition that is characteritized by the complete or partial absence of the iris. It has a high association with glaucoma (75%) due to angle closure from PAS. Patients often have poor vision due to fovea hypoplasia with a subsequent nystagmus. Additional ocular associations include microcornea, lens subluxation, and ONH hypoplasia

Answer 261

◦ Extends from the pupil margin to the iris root. It contains multiple fibroblasts, melanocytes, and collagen fibrils. Provides definitive color to the iris.

Answer 262

◦ Iris color is determined by the amount of melanin within iris melanocytes, NOT THE AMOUNT OF MELANOCYTES within the anterior border layer

Answer 263

the anterior border layer is thin and melanocytes continually on a small amount of melanin

Answer 264

the anterior border layer is thick and the melanocytes contain a very large amount of melanin

Answer 265

◦ In both light and dark colored irises, the two iris epithelial layers are heavily pigmented. Th only condition characterized by a lack of pigment within the iris epithelial layers is oculocutaneous albinism

Answer 266

collagenous columns located in the anterior border layer that serve as passageways for aqueous humor to enter the iris stroma. They give the anterior iris surface a rough appearance

Answer 267

inflammation strips melanin, always shifts towards blue

Answer 268

• Difference in iris color between eyes. It can be congenital or from other factors such as topical prostaglandins use or chronic inflammation (uveitis)

Answer 269

• Vascularized, loose collagen network with fewer cells than the anterior border layer. It is continuous with the stroma of the CB. The iris stroma contains several important elements

Answer 270

fibroblasts, melanocytes, lymphocytes, macrophages, mast cells, and clump cells

Answer 271

LPCNs, and SPCNs. Sensory and sympathetic fibers are carried within the LPCNs and the SPCNs. Parasympathetic fibers are carried within the SPCNs

Answer 272

caps are non-fenestrated (zonula occludens junctions) and form part of the blood aqueous barrier

Answer 273

located in the CB close to the iris root and extends radially through the iris stroma up to the pupillary margin. It is formed by anastomoses between the LCPAs and the anterior ciliary arteries

Answer 274

located within the iris stroma near the pupillary margin and inferior to the collarette. It is formed by anastomoses of the radial arteries that branch from the major arterial circle of the iris

Answer 275

radial veins of the iris parallel the radial arteries. They drain blood from the iris into the CB veins-choroidal veins-vortex veins-superior/inferior ophthalmic veins

Answer 276

circular smooth muscle anchored firmly in the iris stroma and to the dilator muscle. The sphincter muscle originates from the anterior iris epithelial cells that detach and migrate into the iris stroma and become smooth muscle cells. It is innervated by CN III parasympathetic fibers traveling with the SPCNs. Parasympathetic stimulation results in pupil constriction

Answer 277

Malenin | Eye color

Answer 278

Blood vessles Minor arterial circle Sphincter

Answer 279

Pupillary ruff | Pigment dispersion syndrome

Answer 280

• anterior iris epithelium: lies closest to the iris stroma and extends posteriorly to become the pigmented epithelium of the CB. Contains pigmented myoepithelial cells that contain muscular processes at the basal surface that extend into the iris stroma and attach to the iris sphincter muscle, forming the dilator muscle. D

Answer 281

extends radially from the iris root into the pupillary zone and terminates at appx the midpoint of the iris sphincter muscle. Sympathetic stimulation of the dilator muscle results in dilation of the pupillary portion of the iris and is pulled towards its origin at the itis root

Answer 282

• heavily pigmented single layer of columnar cells attached to the pigmented anteiror iris epithelium. It extends posteriorly to become the NPCE-then the sensory retina ◦ The pupillary ruff is formed by the posterior and anteiror iris epithelial layers curling anteriorly towards the anteiror border layer of the iris

Answer 283

pigment release from the heavily pigmented iris epithelial layers rubbing against the lens zonules, resulting in peripheral iris transilumination defects. Releases pigment may accumulate on the anterior capsule, iris surface, corneal endothelium, or TM and may result in subsequent glaucoma due to poor aqueous outflow

Answer 284

apex to apex by desmosomes and microvilli. Iris cysts can develop there is their is a separation between the two epithelial layers

Answer 285

• located between the iris and the anterior vitreous and is bound by the posterior surface of the iris, the anterior face of the vitreous, the equatorial region of the lens, and the CB. It has a total volume of apex 0.060mL. Composed of three regions

Answer 286

◦ Posterior chamber proper: bound by the posterior iris epithelium, the ciliary processes, and the anterior zonules and surface of the lens ◦ Canal of Hanover: aka circumlental space. Located between the anterior and posterior lens zonules over the equator of the lens. Also contains the equatorial zonules ◦ Canal of petit: aka retrolental space. Located between the most posterior lens zonules, the anterior hyaloid membrane, and the posterior portion of the CB

Answer 287

ciliary body

Answer 288

◦ Aqueous humor production: the NPCE cells produce and secrete aqueous humor into the posterior chamber ◦ Accommodation: CN III parasympathetic fibers in the SPCNs from the cilairy ganglion innervate the CB and cause contraction and subsequent accommodation

Answer 289

wide anterior portion that contains 70-80 ciliary processes that extend into the posterior chamber

Answer 290

heavily pigmented areas located between the ciliary processes

Answer 291

Pars plicata

Answer 292

pars plicata-posterior chamber-pupil-anterior chamber-TM

Answer 293

flatter, more posterior portion that begins at the pars plicata and extends posteriorly to the ora serrata; it serves as the anterior border of the retina, located 5mm anterior to the equator

Answer 294

extensions of the peripheral retina (ora serrata) onto the ciliary body (pars plana)

Answer 295

posterior extensions of the pars plana that lie between the dentate processes

Answer 296

• Neighboring dentate processes can join together, forming an enclosed oral bay; this can be confused with a retinal hole

Answer 297

arise within the tertiary vitreous from the BM of the NPCE in the pars plana and from the valleys between processes in the pars plicata

Answer 298

extend first to the valleys of Kuhnt of the pars plicata before inserting into the lens capsule

Answer 299

Cause subluxation or dislocation of the lens

Answer 300

outermost layer. Loosely attached to the underlying sclera. It is a potential space filled with loose CT with numerous collagen bands

Answer 301

suprachoroidal (outer layer of the choroid) at the ora serrata. Blood vessels and nerves travel from the suprachoroidal through the supraciliaris to reach the anterior portion of the eye

Answer 302

ciliary body detachment

Answer 303

largest intrinsic muscle of the eye. Composed of smooth muscle fibers that are responsible for accommodation. Innervated by CN III parasympathetic fibers. Anchored anteriorly to the scleral spur and posteriorly in the stroma of the choroid. Contains 3 types of fibers: longitudinal, radial, and mullers annular muscle

Answer 304

outermost fibers that comprise the largest proportion of CM fibers. Form a V shape, originating at the scleral spur and the TM, with legs extending into the choroid as stellate-shaped terminations (muscle stars)

Answer 305

V shaped from the scleral spur. Terminate by inserting into the CT near the base of the ciliary processes

Answer 306

circular muscle bundles that comprise the smallest proportion of the CM fibers. The most medial ones. Located near the MACI. Originate from the scleral spur and have action similar to iris sphincter when activated

Answer 307

between the CM and the epithelial layers. Highly vascularized and contains the MACI

Answer 308

In the ciliary stroma located inward from the CM near the iris root. It contains large, fenestrated caps located near the ciliary epithelium of the pars plicata that are formed by anastomoses of the LPCAs and the anterior ciliary arteries

Answer 309

‣ Although large substances are capable of exiting the blood from the fenestrated caps, the tight zonular junctions of the NPCE regulates the release of these molecules into the anterior chamber ‣ As an example, the protein concentration in the blood is 7% compared to only 2% in the aqueous humor

Answer 310

produced from plasma that escapes the blood stream via the fenestrated caps of the MACI

Answer 311

composed of two layers of epithelium that line the ciliary body and are joined apex to apex via zonulae occludens to form part of the BAB. Both epithelial layers contain highly active cells

Answer 312

outer cuboidal epithelial layer that is attached to the ciliary stroma via the basal lamina of the BM ‣ Anterior: continuous with the pigmented anteiror iris epithelial and its BM ‣ Posterior: continues with the RPE and the inner BM portion of Bruchs membrane

Answer 313

inner cuboidal/columnar epithelial layer that lines the posterior chamber. Lens zonules arise from the basal lamina at the pars plana and the valleys of the pars plicata. Also contains numerous organelles that are necessary for aqueous secretion.

Answer 314

* branches from the LCPAs and the MACI supple blood to the CB * Veins within the CB eventually drain through the vortex veins

Answer 315

* CN III parasympathetic nerve fibers travel with SPCNs from the ciliary ganglion to supply the CM for accommodation * Sympathetic nerve fibers from the superior cervical ganglion of the sympathetic ganglion chain travel with the LPCNs and the SPCNs to innervate arteries within the CB * Sensory nerve fibers from the trigeminal ganglion of V1 travel with LCPNs to the CB

Answer 316

MACI (CB) | Choroid

Answer 317

minor arterial circle of iris | Retina

Answer 318

* located between the sclera and the RPE and extends from the ora serrata to the optic nerve * Thickest in the posterior pole and thinnest at the ora serrata

Answer 319

1. Suprachoroidal lamina (lamina Fusca) 2. Choroidal stroma 3. Choriocapilaris 4. Bruch’s membrane

Answer 320

potential space located between the sclera and the choroidal vessels. It is loosely packed with collagen fibers, fibroblasts, melanocytes, and extracellular matrix ◦ Serves as the passage for the LPCAs and the LPCNs that travel from the posterior to the anterior region of the eye ◦ The suprachoroidal layer contains components of BOTH the choroid and the sclera (it does not belong exclusively to the choroid). If the choroid and sclera are separated, part of the suprachoroid will adhere to the sclera and part will adhere to the choroid

Answer 321

loose CT layer that contains choroidal blood vessels, nerves, and dense melanin granules ◦ The choroidal vessels are innervated by the sympathetic nervous system, which causes vasoconstriction ◦ The high density of blood vessels and melanin granules within the choroidal stroma creates the potential space for the development of choroidal melanomas

Answer 322

the mid equatorial region to the ora serrata along the 3 and 9 o clock meridians

Answer 323

Choroidal melanoma

Answer 324

Haller’s layer | Sattler’s layer

Answer 325

posterior layer composed of large vessels that branch into smaller vessels that form Sattlers layer. The tributaries of the vortex veins are also located within Haller veins. It’s not good if you can see these. They are the large orange vessels

Answer 326

anterior layer composed of smaller vessels that branch for form a cap bed. The veins that drain blood from the cap bed are the large vortex veins. Unlike most veins i nthe body, vortex veins DO NOT contain valves

Answer 327

composed of large bed of fenestrated capillaries that are most concentrated within the macula. Provides nourishment to the outer layers of the retina. ◦ Contains few pericytes that surround the cap walls and provide local regulation of blood flow. (Damaged in DM)

Answer 328

‣ DM can damage the blood vessels and pericytes of the choroid, preventing proper diffusion of nutrients and O2 to the macula and resulting in diabetic retinopathy.

Answer 329

the thin (2um) innermost loafer of the choroid that extends from the optic nerve to the CB. It represents the fusion of th echoriocapillaris and the RPE BM. Bruchs membrane is composed of the following 5 layers ‣ BM of the choriocapillaris ‣ outer collagenous layer ‣ Elastic layer (very strong) ‣ Inner collagenous layer (Drusen in AMD) ‣ BM of the RPE

Answer 330

pass from the choriocapillaris through Bruch’s membrane and into the retina

Answer 331

pass from the retina through Bruchs to the choriocapillaris

Answer 332

accumulate on Bruchs membrane with age, causing it to become hydrophobic; this impedes water movement, thereby inhibiting the transport of metabolites.

Answer 333

deposits of waste material from the retina between the inner collagenous layer of bruchs and the the BM of the RPE. They occur as a result of the decline in nutritional supply to the retina and are the characteristic finding in AMD

Answer 334

• Result from a break in bruchs membrane that can occur in a variety of conditions including exudative AMD, pathological myopia, histoplasmosis, choroidal rupture, best disease, and pseudxanthoma elasticum (angioid streaks)

Answer 335

``` ◦ Angioid streaks result from damage to the elastic layer of bruchs. Remember PEPSI for Association’s with angioid streaks ‣ PXE ‣ Ehlers danlos ‣ Pagets ‣ Sickle cell ‣ Idiopathic ```

Answer 336

``` ‣ Choroidal rupture (trauma) ‣ Histo (choroiditis) ‣ Best (lipofuscin in breaks) ‣ ADM (wet, free radicals) ‣ Lacquer cracks (high myopia) ‣ Angioid streaks (PEPSI) • All of these can cause a PED • Number one reason people go blind in US is because of a break in Bruchs ``` CHBALA

Answer 337

◦ LPCAs nourish the anteiror choroid ◦ Branches of the SPCAs for mthe choriocapillaris and provide blood to postieror choroid ◦ Vortex veins drain the choroid

Answer 338

LPCNs/SPCNs carry parasympathetic, sympathetic, and sensory fibers to innervate the choroid ‣ Sympathetic fibers from the superior cervical ganglion cause vasoconstriction of the chorodial vessels ‣ CN VII parasympathetic fibers from the pterygopalatine ganglion cause vasodilation of the choroidal vessels ‣ CN III parasympathetic fibers originate from the ciliary ganglion and have an unknown function within the choroid ‣ CN V1 provides sensory innervation to the choroid

Answer 339

4mL; thus it makes up appx 80% of the globe and is easily the largest single structure of the eye

Answer 340

spherical in shape except anteriorly, where it is concave due to the presence of the lens. This bowl shaped depression in the anterior vitreous is called the patellar fossa

Answer 341

• appx 98.5-99.7% H20 within a matrix of type II collagen and HA. Consistency is deterred by the interaction between the collagen fibrils and HA ◦ Early in life, the vitreous is almost entirely gel, by age 70-80, the vitreous is evenly composed of liquid gel and gel ◦ Most of the changes in the collagen fibril/HA complex occur within the central vitreous Halocytes Fibroblasts

Answer 342

predominate cell type. Exclusively located in the vitreous cortex. Responsible for synthesizing HA and may have phagocytic properties

Answer 343

predominately located int he vitreous base and likely synthesize collagen fibrils

Answer 344

occur whrn the HA/collagen complex is disrupted and the collagen clumps up in bundles. Over time, liberated collagen can contract within the vitreous gel, causing posterior hyaloid membrane to detach from the retina, resulting in a posterior vitreous detahcment (PVD). A Weiss ring is formed when the posterior hyaloid completely detaches from the optic disc

Answer 345

``` Vitreous base (ora) Posterior lens Optic disc Macula Retinal vessels ```

Answer 346

The ora with a 3 mirror

Answer 347

Weiss ring

Answer 348

Glial cells from back of viretous and inside the retina | Mac hole from vitreous traction/VMT

Answer 349

Preretinal/vitreous heme

Answer 350

◦ Outer region of the vitreous adjacent to the retina that extends to the ora serrata. Consists of a high density gel filled with collagen fibrils, cells, proteins, and a mucopolysaccharide filler substance. The vitreous cortex is divided into anterior and posterior hyaloid regions by the vitreous base, an area at the ora serrata tha that the strongest attachment to the vitreous.

Answer 351

extends from the vitreous base anteriorly to attach to the lens

Answer 352

depression of the anterior vitreous caused by the posterior Lens

Answer 353

strong circular adhesions between the anterior vitreous, postieror zonules, and the posterior capsule of the lens

Answer 354

a potential space between the anterior hyaloid and the posterior lens capsule that is located in the central area of the non-adhesion withi nthe circular hyaloideocapsular ligament

Answer 355

begins at the posterior edge of the vitreous base and extends posteriorly to the optic disc

Answer 356

A normal remnant of the primary vitreous that is located in the center of the vitreous cavity. It is composed of a channel of low density liquid vitreous surrounded by a wall of high density gel vitreous ‣ Represents the former site of the hyaloid artery that was responsible for nourishing the avascular lens during embryological development ‣ After development, the hyaloid arter regresses to the optic disc where is becomes the CRA ‣ The posterior end of the canal near the optic disc is known as the area of martegiani.

Answer 357

located on the anterior lens capsule; it is the embryological remnant of the former connection between the anterior tunica vasculosa lentis and the posterior hyaloid artery

Answer 358

embryological remnant of the hyaloid artery on the posterior lens capsule

Answer 359

embryological remnant of the hyaloid artery on the optic disc.

Answer 360

Neural ectoderm

Answer 361

RPE-PR-ELM-ONL-OPL-INL-IPL-GCL-NFL-ILM

Answer 362

• single layer of cuboidal pigmented cells. The apical side of the cells face the retina and the basal side lies adjacent to bruchs membrane. The BM of the RPE strongly adheres to the choroid, forming the innermost portion of bruchs membrane

Answer 363

Outer layer of the optic cup

Answer 364

◦ Although RPE has NO intercellular junctions with the rods and cones, the apical side of the RPE cells contains microvilli that extend into the PR layer to surround the PR outer segments. These microvilli are responsible for phagocytosis of the PR outer segments

Answer 365

is filled with interphotoreceptor matrix that has a varied chemical composition around rods compared to cones

Answer 366

lead to the deployment of retinal detachments

Answer 367

1. Phagocytosis of PR outer segments 2. Transfer of ions, water, and metabolites 3. Vitamin A storage and metabolism 4. Blood retinal barrier 5. Absorbs light 6. Produces growth factors for tissue maintenance

Answer 368

RPE cells are highly active and contain smooth ER, rough ER, golgi, and lysosomes. Undigested material from outer segments can accumulate within RPE cells as lipofuscin, which can contribute to RPE cell death

Answer 369

lysosomes are found within RPE cells and play a significant role in phagocytosis of the PR outer segment layer

Answer 370

RPE cells transport substances between the choroid and retina through a complex process that involves multiple pumps, co-transporters, and channels. Examples include the following ‣ Proton-lactate water cotransporter moves lactate, a byproduct of anaerobic respiration from the RPE to the choroid ‣ Glucose transporter moves glucose from the choroid to the RPE to ensure a steady supply to the PR

Answer 371

Proton-lactate water cotransporter

Answer 372

Moves glucose from the choroid into the RPE to ensure a steady supply to the PR

Answer 373

RPE cells play an important role in the visual cycle by recycling vitamin A (all-trans retinol) and retinoids between the PR and the RPE

Answer 374

RPE cells are tightly linked together by a terminal complex that includes zonules occludens, zonulae adherents, and maculae adherents, forming the blood retinal barrier

Answer 375

RPE cells contain pigment granules that absorb stray light that is not absorbed by the rods and cones

Answer 376

RPE cells produce VEGF which is essential for choroicapillaris function, as well as pigment epithelial derived factor (PEDF), an antiangiogenic factor that counterbalances the effects of VEGF

Answer 377

Inner layer of the inner segment that contains ER and Golgi apparatus for protein synthesis Myopia=makes protein

Answer 378

The outer layer of the inner segment that is packed with mitochondria Ellipsoid=energy

Answer 379

Connects the outer and inner segments of the PR

Answer 380

contains stacks of membranous discs that contain photopigments produced by the inner segment ‣ The outer segment produces the discs that surround the photopigment molecules. There are appx 600-1000 discs per rod and 1000-1200 per cone ‣ Disc membranes are continues with the plasma membrane in cones but are free floating (NOT continuous with the plasma membrane) in rods

Answer 381

in the inner segment assembled into discs at the base of the outer segment, and are continually shed at the tip of the outer segment for phagocytosis by the RPE

Answer 382

◦ Used for scotopic vision; rods detect objects under low levels of illumination ◦ Rod density is greatest about 5mm (20 degrees) concentrically from the fovea in an area known as the rod ring ◦ Rod discs contain photopigment rhodopsin, which absorbs photons maximally at 507nm; rhodopsin DOES not detect color ◦ Rods terminate in spherules (compared to cones, which terminate in pedicles)

Answer 383

Used for photopic vision. Cones contain 3 different photopigments (iodopsins) that each contain the same chromophore (11-cis-retinal) but differ in their protein (opsin) component ‣ Cyanolabe (blue): max absorbs at 440nm ‣ Chlorolabe (green): 535nm ‣ Erythrolabe (red): 565

Answer 384

The fovea is 5mm temporal and 0,4mm inferior to the center of the ONH (superior and nasal to the ONH if viewing with a 78 or 90D condensing lens) and contains ONLY cone photoreceptors at the highest concentration in the retina

Answer 385

• not a true membrane and does not contain any cells. It is formed by a band of desmosomal attachments between muller cells and the inner segments of the PR. Ir provides structure to the retina and acts as a barrier against large metabolites

Answer 386

• contains the cell bodies of the rods and cones

Answer 387

• location of synapse between rod spherules and cone pedicles and the dendrites of bipolar and horizontal cells

Answer 388

each rod spherules can synapse with 1-4 rod bipolar cell dendrites (the ONLY type of bipolar cell rods synapse to). Horizontal cell dendrites may also connect to rod spherules

Answer 389

larger than rod spherule. Can form a synaptic triad that consists of 3 horizontal cell dendrites OR 2 horizontal cell dendrites on either side of 1 bipolar cell dendrite with an invagination in the cone pedicle. ◦ Cone pedicles may synapse with midget, flat, or diffuse flat bipolar cells

Answer 390

NFL, GCL, IPL, and INL, and a portion of the OPL.

Answer 391

Splitting of the OPL

Answer 392

• location of the synapse between the 2nd order (bipolar) and 3rd order (ganglion cell) neurons in the visual pathway. Amacrine cells modify the synapse between the bipolar and ganglion cells by providing temporal input and increasing signal resolution

Answer 393

One process from an amacrine cell and one dendrite from a ganglion cell

Answer 394

Bipolar cells, ganglion cells, interplexifme cells, and amacrine cells within the IPL

Answer 395

RP, bipolar, ganglion

Answer 396

Horistonal | Amacrine

Answer 397

• the location of the ganglion cell bodies. Each ganglion cell has a single axon that travels within the optic nerve and terminates in the LGN or other areas of the brain

Answer 398

In the foveola

Answer 399

parvocellular cells have small diameter axons and are sensitive to color and fine detail. More common than M cells and project to the parvocellular layers of the LGN (3/4/5/6).

Answer 400

midget ganglion cells. Most common ganglion cells and contain only one dendrite that synapse with one midget bipolar cell, which connects with one cone PR within the fovea

Answer 401

larger, contain multiple dendrites that synapse multiple bipolar cells

Answer 402

magnocellular cells have larger diameter axons and are sensitive to dim changes in illumination and motion. M cells reject to the magnocellualr layers of the LGN (1 and 2)

Answer 403

M cells and P cells

Answer 404

‣ Midget ganglion cells are responsible for resolving fine detail because they carry visual info from a single cone PR within the fovea

Answer 405

• composed of axons of ganglion cells that collectively form the ON

Answer 406

At the superior and inferior optic disc margin where the largest proportion of axons enter the optic nerve

Answer 407

In the fovea

Answer 408

consists of the NFL fibers that extend from the macula and insert on the temporal margin of the optic disc ‣ The superior and inferior temporal fibers arc over the papillomacular bundle and insert at the superior and inferior margins of the optic disc ‣ The superior and inferior nasal fibers insert directly into the superior and inferior nasal margins of the optic disc

Answer 409

* CWS: soft exudates, located within the NFL an most commonly caused by DM * Splinter hemorrhage: drance heme, hemes that occur within the NFL at or near the disc margin * Flame hemorrhage: within the NFL and are associated with retinal vascular pathology

Answer 410

assocaited with deep retinal vascular pathology and are found within the INL. CWS, splinter hemes, and flame hemes, are associated with superficial retinal vascular pathology and are found within the NFL

Answer 411

• the innermost boundary of the retina (closest to the vitreous) that is continuous with the inner limiting membrane of the ciliary body. The ILM is comprised of the footplates of muller cells and their basal lamina and are bound to vitreous humor collagen fibrils ◦ The ILM is present over the macula but NOT over the optic disc. Astrocytes replace the footplates of muller cells at the optic disc ◦ Epiretinal membranes occur on the ILM and are commonly located within the macula

Answer 412

Over ther ONHY

Answer 413

Astrocytes

Answer 414

‣ 128 mill PR-35 mill bipolar cells-1.5mil ganglion cells ‣ the neural message is highly refined from the PR to the ganglion cells ‣ The optic nerve acts like a bottleneck through which all visual information must pass through.

Answer 415

Muller cells Astrocytes Microglial cells

Answer 416

the most common glia cell that is present exclusively in the retina. Extend from the ELM to the ILM. Most cell bodies located within the INL ◦ Although not found within the PR layer, microvilli from the apical surface of muller cells may extend towards the inner segments of the PR to form fiber baskets

Answer 417

‣ Maintain alignemtn of other neurons within the retina ‣ Provide nutrients to the retina and aid in glycogen metabolism ‣ Act as a buffer and regulate electrolyte concentration within the extracellular space (particularly K+ concentration) ‣ Absorb and recycle metabolic waste products such as GABA and glutamate

Answer 418

◦ Retina is highly metabolic. It’s primary source of energy is glucose that is produced via anaerobic glycolysis. O2 and nutrients are transported across the RPE into the inner segments of the PR. Excess glucose is converted to glycogen and stored in muller cells to ensure the PR have a constant supply of nutrients.

Answer 419

most concentrated within the inner retinal layers. Fibrous cells that provide structure to nerve fibers and retinal caps ◦ Astrocytes help form the ILM at the optic disc (muller cells form the ILM throughout the rest of the retina). They perform similar functions as muller cells

Answer 420

phagocytic cells that respond to inflammation and/or injury. Microglial cells can be found anywhere in the retina.

Answer 421

◦ Neuroglial cells have NO ROLE in signal processing. They provide protection and structural support to the retina.

Answer 422

Choroida | Vortex veins

Answer 423

Superficial network in the NFL | Deep cap in the INL (near the OPL)

Answer 424

supplies the inner layers of the macula. It is present in 15-20% of the population and allows the macula to be spared in a CRAO

Answer 425

• Retinal arteries and veins share a common adventitious at AV crossings. Because of this close relationship, damage to the arterial walls resutls in venous wall compression and thrombus formation. This explains why almost all branch retinal vein occlusion occur at AV crossings.

Answer 426

3.5mm from the lateral edge and 1mm inferior

Answer 427

zeaxanthin and lutein) that are responsible for reducing chromatic aberration and may provide protection against free radicals. Mostly found withinin the inner segments of the PR (and to a lesser extend, in the outer segments of the rods); they contribute to the more yellow appearance of the macula compared to the surrounding retina.

Answer 428

1DD | 1.5mm diamter

Answer 429

‣ The central 0.40-0.50mm of the fovea is avascular in order to minimize light scattering and allow for resolution of fine details. This area is supplied by the underlying choriocapillaris via the SPCAs

Answer 430

0.35mm diamter 0.13mm thickness Last area of the retina to mature during development

Answer 431

ONLY PR The ganglion cells, bipolar cells, and other retinal cells are displaced laterally in order to minimize light scattering

Answer 432

Foveola Area of best VA

Answer 433

S cones | Rods

Answer 434

RPE, PR, ELM, Henle’s fiber layer, and ILM

Answer 435

term used for the OPL at the macula. This layer contains the axons of PR. There are no bipolar cells or ganglion cells withi nthe fovea or foveola (and thus not INL, IPL, GC layer, or NFL)

Answer 436

◦ 0.5mm zone that surrounds the fovea (1mm). The clivus (sloping of the retinal layers within the macula) marks the boundary between the parafovea and the fovea. ALL retinal layers are present within the parafovea ‣ The parafovea is the thickest area of the retina and contains the largest number of bipolar cells (7-11 layers) and ganglion cells (7-11)

Answer 437

◦ 1.5mm zone that surrounds the parafovea (total 3mm) ‣ Boundary between the peri and parafovea is the location where the ganglion cell layer becomes 4 cell layers thick. Boundary between the perifovea and the periphery is where ganglion cell layer is one cell thick

Answer 438

Density of rods increases at 1.2-1.7mm from the center of the fovea. Density peaks 5mm from the center of the fovea and forms the rod ring just outside perifovea

Answer 439

5mm anterior to the equator of the eye at the ora serrata

Answer 440

2mm band at the anterior most portion of the retina and is composed of dentate processes and oral bays ‣ Dentate processes are extensions of peripheral retina onto pars plana of the CB ‣ Oral bays are extensions of pars plana into the peripheral retina

Answer 441

◦ The RPE becomes the pigmented ciliary epithelium ◦ The neural retina significantly thins and transitions into the NPCE ◦ The vitreous base, the strongest attachment between the vitreous and the retina extends over and posterior to the ora serrata ◦ Retinal vasculature becomes very limited towards the ora seratta. The peripheral 1.5mm of anterior retina contains very few, if any, capillaries

Answer 442

1,2,5,7,8,9,10

Answer 443

3,4,5,6,7,9,,10,11,12

Answer 444

5, 7, 9, 10

Answer 445

Facial expression | Ant 2/3 tast, lacrimation, salivation

Answer 446

Swallow, salivate, post 1/3 taste

Answer 447

Taste, swallow, palate elevation, talk, viscera

Answer 448

Head turn | Shoulder shrug

Answer 449

Tongue movement

Answer 450

Uvula away from the side of the lesion and the palate does not elevate. Patient will report a hoarse voice

Answer 451

Tongue towards the side of the lesion

Answer 452

◦ Sensory information only. Composed of axons of ganglion cell bodies within the GCL of the retina. All axons converge at the optic disc, exit the sclera at the lamina cribrosa, and leave the orbit via the optic foramen to travel through the optic canal

Answer 453

from GC bodies nasal to the fovea) cross at the optic chiasm to join the temporal fibers of the other eye within the optic tract

Answer 454

• The optic tract contains nasal fibers from the contralateral eye and temporal fibers from the ipsilateral eye that carry info from the same side of the visual field

Answer 455

* LGN: relates visual information to the primary visual cortex (V1) * Pretectal nucleus: involved in pupil innervation * Superior colliculus: saccades

Answer 456

◦ CN III has a right and left nucleus located in the midbrain at the level of the superior colliculus. Each nucleus contains sub-nuclei that proved voluntary motor control to the SR, MR, IR, and IO muscles, as well as an EW nucleus that provides parasympathetic innervation to the ciliary and iris sphincter muscles through the ciliary ganglion

Answer 457

‣ CN III nuclei are connected to the nuclei of CN IV, VI, and VIII through the medial longitudinal fasciculus (MLF). They also receive information from the superior colliculus and the visual cortex

Answer 458

Superior rectus CONTRA SR

Answer 459

Only one central subnucelus of CN III

Answer 460

Will resutls in a sudden onset bilateral ptosis

Answer 461

◦ Fibers fro mthe sub-nuclei join together as they exit the brainstem and then travel in close proximity ro the PCA before piercing the roof of the cavernous sinus. Within the cavernous sinus, CN III receives sympathetic fibers from the ICA plexus. CN III divides into superior and inferior divisions just before it enters the superior orbital fissure

Answer 462

• Innervated the SR and superior levator palpebrae muscle. Sympathetic fibers travel with the superior division to innervate mullers muscle of the upper eyelid

Answer 463

* Innervated the MR, IO, IR, iris sphincter muscle, and ciliary muscle * The inferior division contains parasympathetic fibers from the EW nucleus that course to the CG; these fibers leave the ganglion as SPCNs and innervate the iris sphincter and the ciliary muscle for pupillary contrition and accommodation.

Answer 464

located on the outside of all other fibers within CN III. This is important to understand if a CN III lesion is an emergency or not

Answer 465

should immediately raise suspicion for an aneurysm of the PCA. The pupil is invovled because of the aneurysm pushing on the pupillary fibers on the outside of the CN III

Answer 466

Junction between the PCA and the ICA

Answer 467

likely caused by ischemia of the small blood vessels that nourish the inner fibers of CN III, most likely as a result of DM or HTN. Since the pupil is not involved, the likelihood of a compressive lesion pushing on CN III is low

Answer 468

◦ Longest and skinniest nerve ◦ Contains two nuclei that are located in the midbrain at the level of the inferior colliculus ◦ The CN IV nuclei are connected to the nuclei of CN III, VI, and VIII through the MLF. They also connect to the superior colliculus via the tectobulbar tract, which then connects to the visual cortex ◦ TCN VI is the ONLY cranial nerve that leaves the dorsal side of the midbrain and decussates to innervate the contralateral SO muscle

Answer 469

4 | Contra SO

Answer 470

Lesser wing

Answer 471

Provides sensory information from the head to the tip of the nose

Answer 472

Provides sensory info from the side of the nose to the mouth

Answer 473

Provides sensory info from the the head and ear to the mandible. It also provides motor info to the muscles of mastication

Answer 474

‣ The sensory fibers travel from the face and head structures, through the cavernous sinus and synapse in the trigeminal ganglion (posterior portion of the cavernous sinus) before traveling to the sensory nuclie in the pons to relay to the thalamus.

Answer 475

* Spinal nucleus: medulla, pain and Temp from ipsilateral face * Main sensory nucleus: pons, light touch * Mesencephalic nucleus: pons, mediates proprioception

Answer 476

• Herpes simplex keratitis can affect any or all of the branches of V1. This, these patients are much more likely to have involvement of the upper eyelid and forehead rather than the lower eyelid and forehead

Answer 477

Nasociliary Frontal Lacrimal

Answer 478

V1 sensory info from the cornea, iris, and tip of the nose. It has several branches including the long ciliary nerves, short ciliary nerves, intfratrochlear nerves, and the anterior and posterior ethmoid nerves • The LPCNs: sensory to cornea, iris, Ciliary muscle. Sympathetic fibers to the dilator muscle of the iris • SPCNs: sensory fibers to cornea, iris, ciliary muscle • Infratrochlear nerve: sensory fibers to the medial angle of the eyelids

Answer 479

◦ Branches from the nasociliary nerve of V1 innervate the cornea and the tip of the nose. This explains why Hutchinson’s sign indicates a high likelihood of corneal involvement in herpes zoster

Answer 480

V1 branches in the cavernous sinus just before it enters the orbit through the superior orbital fissure. The frontal nerve divides into two terminal branches

Answer 481

Supratrochlear | Supraorbital

Answer 482

Frontal branch passes just superior to the trochlea of the SO to ultimately provide sensory innervation for the skin and muscles of the forehead and the medial portion of the upper eyelid and conjunctiva

Answer 483

Branch of the frontal | provides for the forehead and scalp, the central portion of the upper eyelid and the conjunctiva

Answer 484

Branch of V1 sensory feedback for the lacrimal nerve • Just before it enters the lacrimal gland, the lacrimal nerve receives parasympathetic fibers of CN VII from the zygomatic branch of V2; these fibers are responsible for lacrimation • Once it leaves the lacrimal gland, the lacrimal nerve pierces the orbital septum to supply the lateral conjunctiva and ther lateral part of the upper eyelids

Answer 485

Maxillary division ‣ Travels along the inferior lateral portion of the cavernous sinus before entering the foramen rotundum of the greater wing of the sphenoid. V2 divides into two terminal branches just before entering the orbit through the inferior orbital fissure

Answer 486

Infraorbital nerve | Zygomatic nerve

Answer 487

Branch of V2 ‣ Travels along the inferior lateral portion of the cavernous sinus before entering the foramen rotundum of the greater wing of the sphenoid. V2 divides into two terminal branches just before entering the orbit through the inferior orbital fissure

Answer 488

Branch of V2 courses laterally from the inferior orbital fissure and divides into the terminal branches that innervate LATERAL structures, including the lateral aspect of the forehead, the lateral side of the cheek, and the lateral aspect of the lower eyelid. Remember, the zygomatic nerve of V2 carries parasympathtic fibers from the pterygopalatine ganglion of CN VII to the lacrimal nerve of V1 to stimulate lacrimation

Answer 489

zygomatic, maticofacial, infraorbital, infratrochlear. Note that the infratrochlear nerve (a branch of the nasociliary nerve) provides nerve supply to the medical portion of the lower lid (majority) and the upper lid

Answer 490

Mandibualr branch ‣ Provides sensory innervation to the lower face ‣ Provides motor innervation to the muscles of mastication

Answer 491

◦ Located in the pons. Fibers leave the nucleus between the pons and medulla and then make a tight bed over the petrous ridge of the temporal bone before entering the cavernous sinus

Answer 492

CN 6 CN VI palsy can also result from an ICA aneurysm with the cavernous sinus due to the close association between the ICA and the CN VI as they travel through the cavernous sinus

Answer 493

Toward the affected side

Answer 494

◦ Motor innervation to the muscles of facial expression and supplies parasympathetic fibers to the inner ear and facial glands (including lacrimal gland). The facial nerve also carries taste sensation (sensory) from the anterior 2/3 of the tongue

Answer 495

innervated the facial muscles, including the orbicularis oculi to close the eye

Answer 496

parasympathetic fibers stimulate secretion of the facial glands including lacrimation of the lacrimal gland. The involuntary motor root also provides a branch to the stapedius muscle of the middle ear to dampen sound

Answer 497

carries taste form the anteiror 2/3 of the tongue

Answer 498

‣ Input to CN VII nucleus begins in the precentral motor cortex in the frontal lobe ‣ Fibers descend within the corticobulbar tract to the pons where the facial motor nucleus and the superior salivatory/lacrimal nuclei are located ‣ Fibers exit the nuclei of CN VII as a main motor root and the nervous intermediate root ( carries parasympathetic fibers of CN VII). Fibers arc around the abducens nucleus before exiting the brainstem. They enter the internal auditory canal in the petrous portion of the temporal bone and travel trough the geniculate ganglion ‣ After leaving the geniculate ganglion, the greater petrosal nerve and the chorda tympani nerve branch off the main root of CN VII. The remaining fibers exit the temporal bone of the skull through the stylomastoid foramen. They enter the parotid gland and divide into 5 branches to innervate the muscles of facial expression

Answer 499

CN VII due to the close associated between the two nuclei within the brainstem

Answer 500

Cn VII ‣ Carries parasympathetic innervation to the lacrimal gland. The greater petrosal nerve joins the deep petrosal nerve ( contains post ganglion sympathetic fibers) to form the Vidian nerve ‣ The vidian nerve travels to the pterygopalatine ganglion were parasympathetic fibers synapse ‣ Post ganglion fibers leave the pterygopalatine ganglion and join the zygomatic branch of V2. The zygomatic branch sends a communicating branch to the lacrimal nerve of V1 to innervate the lacrimal gland

Answer 501

Cn VII ‣ Terminal branch of Cn VII that carries taste fibers to the anterior 2/3 of the tongue and provides parasympathetic supply to the submandibular and sublingual glands

Answer 502

‣ The main root of CN VII passes through the stylomastoid foramen and enters the parotid glands, where it divides into the 5 branches (temporal, zygomatic, buccal, mandibular, and cervical branches) to supply the muscles of facial expression. The tow most superficial branches (temporal and zygomatic) innervate the muscles around the eye • The temporal branch innervated the procerus, corrugator, occipital frontalis, and the orbicularis occuli • The zygomatic branch innervated the orbicularis oculi

Answer 503

• Although the facial nerve branches within the parotid gland, it DOES NOT innervate the gland. The glossopharyngeal nerve (CN IX) provides innervation to the parotid gland. Removal of an acoustic neuroma may result in damage to the nearby parotid gland and CN VII, causing facial paralysis on the affected side

Answer 504

‣ Remember that the upper neurons of CN VII in the brainstem receive bilateral input from the cerebral cortex. The lower neurons of CN VII receive contralateral input and provide innervation to the ipsilateral facial muscles ‣ Bell’s palsy: an idiopathic lesion of the lower motor neurons of Cn VII that result in impaired innervation to the upper and lower ipsilateral facial muscles, causing drooping of the mouth, and poor eyelid closure. Can result in paralytic lagophthalmos and secondary exposure keratopathy Always ipsilateral, all of face

Answer 505

‣ Remember that the upper neurons of CN VII in the brainstem receive bilateral input from the cerebral cortex. The lower neurons of CN VII receive contralateral input and provide innervation to the ipsilateral facial muscles -a supranuclear lesion results in impaired innervation to the contralateral muscles of the lower face, often resulting in drooping of the mouth. The contralateral fibers to the upper face that allow eyelid closure and wrinkling of the forehead are after spared, and patient’s are able to firmly close their eyes and wrinkle their forehead Always contralateral, lower side of the face

Answer 506

• originates from the midbrain ( CN III) and the pons (CNVII) and performs 3 major functions ◦ Oculomotor nerve: travels to the iris sphincter and the ciliary muscle for miosis and accommodation ◦ Facial nerve: travels to the lacrimal gland for lacrimation

Answer 507

• 1st order preganglionic fibers begin in the hypothalamus and descend to the C8-T2 region of the spinal cord to synapse in the ciliospinal center of budge. 2nd order pre ganglionic fibers leave the ganglion and travel around the clavicle and across the apex of the lung before entering the sympathetic chain of ganglia around the neck. Fibers ascend the chain and synapse in the superior cervical ganglion. Post ganglionic fibers from the SCG form a plexus around the ICA and enter the skull via the carotid canal

Answer 508

◦ 1. Follow the superior division of CN III to innervate mullers muscle of the upper eyelid ◦ 2. Follow the nasociliary nerve of CN V1 and branch with either the LPCNs or SPCNs ‣ LPCNs: to the iris dilator and the ciliary muscle ‣ SPCNs: choroidal and conjunctival blood vessels ◦ 3. Provide innervation to the blood vessels of the lacrimal gland (causing vasoconstriction) through the vidian nerve (the motor root of the pterygopalatine ganglion)

Answer 509

thought to play a role in the development of central serous chorioretinopathy by contributing to localized damage in Bruch’s membrane

Answer 510

‣ SPCNs: originate from the ciliary ganglion and carry post ganglionic symptthetic and parasympathic fibers to various anteiror structures within the eye. They also carry sensory info from the eye back to the CG via the nasociliary nerve ‣ LPCNs: branch from the nasociliary nerve of V1 as it crosses the optic nerve. They carry post ganglionic sympathetic fibers to the eye, as well as sensory information from the eye back to the trigeminal ganglion ‣ Sensory information carried by both the SPCN and LPCNs is eventually taken to the trigeminal ganglion for analysis

Answer 511

• composed of axons of ganglion cells • Courses to 3 destinations ◦ Midbrain, LGN, superior colliculus

Answer 512

◦ Midbrain, LGN, superior colliculus

Answer 513

surrounded by pia, arachnoid, and dura membranes that are continuous with the meninges of the cranium ◦ The subarachnoid space (between the arachnoid and pia sheaths) of the optic nerve is continuous with the subarachnoid space of the cranium and contains CSF ◦ The dura and arachnoid meninges fuse together and become continuous with the periorbita and the sclera; they DO NOT continue with the intracranial portion of the optic nerve (only the pia mater surrounds the intracranial optic nerve)

Answer 514

results from increased ICP that causes CSF within the subarachnoid space to leak over the superficial optic disc. The disc margins are blurred in papilledema because the CSF spreads over the margins into the surrounding RNFL

Answer 515

provide myelination to the axons posterior to the lamina cribrosa. Astrocytes provide structural support to the optic nerve axons

Answer 516

not found within the optic nerve and therefore DO NOT provide myelination to the optic nerve

Answer 517

‣ The optic nerve sheath is attached to the sheaths surrounding the SR and MR muscles. This association explains why appx 90% of patients with optic neuritis experience pain on eye movement

Answer 518

SPCA and the CRA

Answer 519

supplied by the circle of zinn (SPCAs) and other branches of the SPCAs

Answer 520

supplies by the branches from the CRA and the pial mater arterial plexus

Answer 521

branches of the ophthalmic, anteiror cerebral, anterior communicating, and ICA

Answer 522

the optic nerve is able to auto regulate its blood supply (like the retina but unlike the choroid)

Answer 523

Optic disc

Answer 524

slightly larger vertically (1.75mm) than horizontal (1.50mm)

Answer 525

acts like a blind spot in the VF because it DOES NOT contain a any PR (only NFL and glial membrane produced by astrocytes)

Answer 526

there are NO muller cells over the optic disc. Instead, astrocytes cover the optic disc and form the ILM of Elschnig

Answer 527

1mm | ‣ Portion of the ON that extends from the optic disc to the lamina cribrosa. Can be divided into 2 sections

Answer 528

Pre laminar | Laminar

Answer 529

anteiror the lamina cribrosa. NO MYELIN ◦ The optic nerve fibers are separated from the surrounding retinal tissue by a ring of glial tissue known as the intermediary tissue of Kuhnt. This glial tissue continues posteriorly as the border tissue of Jacoby and separates the optic nerve fibers from the choroid. Scleral collagen fibers at this level also surround the glial tissue, forming the border tissue of Elschnig ◦ Tight junctions within the glial tissue helps to protect the optic nerve fibers from fluid that leaks from the fenestrated chorodial vessels

Answer 530

Prelaminar intraocular portion

Answer 531

section that exits the globe through the lamina cribrosa, a network of collagen and elastic fibers that bridge across the posterior scleral foramen and help support the optic nerve

Answer 532

30mm ‣ Extends postierorly from the lamina cribrosa unit it exits the orbit via the optic canal. This portion of the ON is S-shaped and the axons are separated by CT septae, allowing for eye movements without damage to the ON • The optic nerve axons posterior to the lamina cribrosa become myelinated by oligodendrocyte. The axons are also covered by the meninges that cover the rest of the brain

Answer 533

6-10mm | Portion running through the optic canal

Answer 534

10-16mm | Portion extendin ffrom the optic canal to the optic chiasm

Answer 535

◦ 90% of the optic nerve fibers synapse in the LGN before traveling to the primary visual cortex ◦ Fibers traveling to the superior colliculus aid in saccadic eye movements ◦ Fibers traveling to the pretectal nucleus aid in pupil movement

Answer 536

composed of the fibers from the macula that enter the temporal side of the optic disc. Damage to these fibers can result in central, centric eval, and paracentral visual field defects

Answer 537

macular disease, vit optic nerve disease that affects the papillomacular bundle will also cause reduced visual acuity (nutritional/toxic neuropathy)

Answer 538

axons from retinal ganglion cells nasal to the optic nerve that tenure the nasal side of the disc

Answer 539

axons from ganglion cells temporal to the fovea that enter the disc at the superior and inferior poles, respectively

Answer 540

describes the comparative thickness of the rim tissue, with the inferior rim being thickest and the temporal rim being thinnest

Answer 541

Superior and inferior nasal fibers

Answer 542

inferior nasal fibers that cross through the optic chiasm and then loop anteriorly into the contralateral optic nerve before entering the optic tract

Answer 543

superior nasal fibers that loop posteriorly into the ipsilateral optic tract before crossing through the optic chiasm

Answer 544

‣ The optic tract contains fibers that travel from the optic chiasm to the LGN. Note how the posterior knee (which contains the superior fibers) comes to the medial side of the left optic tract, while the anterior knee (containing inferior fibers) courses to the lateral side of the tract. Macualr fibers are protected in the middle of the tract

Answer 545

located within the circle of Willis. The ICA and posterior communicating arteries travel along the lateral edges of the optic chiasm. The pituitary gland is located inferior to the optic chiasm

Answer 546

extends from the optic chiasm to the LGN and contains fibers (crossed and uncrossed) from each eye that provide information from the same side of the visual field. The optic tract travels along the lateral surface of the cerebral peduncle parallel to the posterior cerebral arteries

Answer 547

‣ Superior fibers (nasal and temporal) course to the medial side of the optic tract. The medial portion of the right optic tract contains right superior temporal and left superior temporal nasal fibers ‣ Inferior fibers course to the lateral side of the optic tract. The lateral potion of the right optic tract contains right inferior temporal and left inferior nasal fibers ‣ Macular fibers travel in the middle of the tract

Answer 548

• fibers within the optic tract synapse at the LGN located within the thalamus. Remember that appx 90% of optic nerve fibers synapse at the LGN before projecting to the primary visual cortex. The LGN is composed of 6 layers that contains three cell types

Answer 549

◦ 1. Magnocellular layers: layers 1 and 2, contain large magno cells ◦ 2. Parvocellular layers: layers 3-6, contain medium parvo cells ◦ 3. Koniocellular layers: contain small cells located between each layer

Answer 550

Superior fibers synapse medial LGN, inferior fibers synapse lateral LGN Macular fibers form a wedge of synapses at the dorsal edge of the LGN and extend throughout its entire thickness SMIL Superior fibers=medial Inferior fibers-Lateral

Answer 551

‣ In addition to serving as the location of the first synapse within the post optic nerve portion of the visual pathway, the LGN also receives fibers from subcortical areas and the primary visual cortex to help fine tune the visual information that is relayed to the primary visual cortex.

Answer 552

The optic radiations

Answer 553

composed of the inferior retinal fibers from the lateral side of the LGN. These fibers travel through the temporal lobe and around the tip of the lateral ventricle into the parietal lobe (forming Meyer’s loop) before terminating in V1 in the occipital lobe.

Answer 554

composed of the superior retinal fibers from the medial side of the LGN. These fibers course directly posterior through the inferior parietal lobe before terminating in V1 in the posterior portion of the occipital lobe

Answer 555

primary visual cortex (V1/Broadmans area 17/striate cortex) is located on the medial surface of the occipital lobe. The calcarine fissure divides the internal posterior portion of the occipital lobe into anterior and posterior sections

Answer 556

the superior portion of the visual cortec in the occipital lobe. Superior retinal fibers terminate here

Answer 557

inferior portion, inferior fibers terminate here

Answer 558

project to the outer surface of the apex of the occipital lobe and make up appx 50% of the fibers within V1

Answer 559

Cuneus gyrus

Answer 560

Lingual gyrus

Answer 561

lower fibers (inferior fibers) course laterally in the optic tract and form Meyer’s loop before ending in the Lingual gyrus

Answer 562

◦ Contains myelinated nerve fibers that mainly project from the LGN, as well as fibers from the superior colliculus and the frontal eye fields. It is organized into 6 horizontal layers and multiple vertical columns of neurons

Answer 563

location of the synapses beterrn the optic radiations and the neurons in the striate cortex. Fibers from the parvo and magnocellular layers of the LGN synapse in different strata within layer 4. Axons projecting from the neurons within layer 4 of V1 travel to higher cortical areas for further visual information processing

Answer 564

sends axons to the superior colliculus for control of saccadic eye movements

Answer 565

provides feedback information back to the LGN

Answer 566

‣ Vertical columns of cells are organized into ocular dominance columns that contain fibers from only one eye. Ocular dominance columns are further organized into stimulus orientation columns.

Answer 567

supplied by the circle of Willis and branches of the ICA

Answer 568

anteiror choroidal branch of the MCA

Answer 569

anterior choroidal and PCA

Answer 570

anterior choroidal, MCA, and PCA

Answer 571

PCA and the MCA ‣ The PCA and the MCA serve as a dual blood supply to the primary visual cortex. If one arterial blood supply is blocked (stroke), vision is often spared because the 2nd arterial blood supply is still able to provide nutrients and O2 to the visual cortex

Answer 572

Tumor is compressing both the MCA and PCA

Answer 573

Macular sparing because there is another blood supply STROKES are macular sparing

Answer 574

produce homonymous visual field defects. This means that the same side of the visual field is affected in both eyes ◦ A right post chiasmal lesion will result in the loss of the left VF in the right AND left eye

Answer 575

the more congruous the visual field defects are between the eyes ◦ Congruity refers to the similarity between homonymous defects in each eye. Remember that fibers from each eye carry visual information about a particular point in the VF travel closer together as they travel more posterior in the visual pathway. Thus, these fibers are often damaged together, producing VF defects with a similar size and shape between the two eyes

Answer 576

congruous defects because it is the most posterior location within the visual pathway

Answer 577

are homonymous defects that DO NOT have a similar size and shape between the two eyes. Lesions that are more anterior in the visual pathway cause incongruous field defects

Answer 578

describes a defect involving one half of the visual field. The location of the lesion cannot be determined based on the appearance of the VF defect, as a lesion anywhere along the visual pathway may result in this type of VF loss. Thus, a complete defect CANNOT be described as congruous or non-congruous. Congruity is reserved for INCOMPLETE homonymous VF defects

Answer 579

superior VF defects. This is often referred to as “pie in the sky”: defect. Remember that a lesion in the temporal lobe damages the inferior retinal fibers forming Meyer’s loop.

Answer 580

inferior visual field defects. This is often referred to as “pie on the floor” defects. Remember that a lesion in the parietal lobe damages superior retinal fibers (and is also associated with asymmetric OKN response)

Answer 581

PITS - parietal=inf VF - temporal=superior VF

Answer 582

unaffected in post chiasmal lesions unless bilateral lesions are present. Remember that in order for VA to be affected, the macular region of the occipital lobe has to lose BOTH of its blood supplies

Answer 583

dual blood supply from the MCA and the PCA

Answer 584

BOTH PCA and MCA are affected ◦ If only one blood supply is affected, vision will remain unaffected (macular sparing) because the other blood supply will continue to provide nutrients to the macular fibers within the occipital lobe

Answer 585

most commonly resutls from a stroke that has affected either the MCA or the PCA (but not both). It is very rare for a stroke to affect BOTH blood supplies of the superficial occipital lobe

Answer 586

most commonly occurs from a tumor that has compressed BOTH blood supplies to the macular cortex. Although it can results from multiple strokes that affect the MCA and the PCA, this is extremely rare

Answer 587

classically caused by a pituitary gland tumor that compresses the nasal fibers from each eye that cross at the optic chiasm

Answer 588

causes a junctional scotoma. This often appears as central vision loss in one eye and superior temporal vision loss in the fellow eye ‣ The eye with the affected optic nerve will have very poor VA. The other eye will have minimal damage (and good VA) because the anterior knee of WIlbrand loops into the damaged optic nerve

Answer 589

indicate a lesion at the optic chiasm

Answer 590

result from lesions anteiror to the chiasm and are most commonly due to glaucoma

Answer 591

result from post-chiasmal lesions and are most commonly due to strokes

Answer 592

strokes. The main exception occurs with macula only homonymous hemianopsias, which are rarely caused by strokes (think compressive lesion!)

Answer 593

◦ Cause asymmetric VF loss between the eyes ◦ Defects typically respect the horizontal midline ◦ Defects may be bilateral but they are NOT congruous ◦ An APD can occur if asymmetrical damage between the optic nerves is great enough ◦ VF defects will correspond to the location of the lesion within the retinal nerve fiber layer

Answer 594

retinal or optic nerve pathology

Answer 595

◦ Causes asymmetrical vision loss between the eyes ◦ Defects DO NOT respect the horizontal or vertical midline ◦ Defects may be bilateral but they are NOT congruous

Ocular Anatomy Flashcards

(653 cards)