Eyes Flashcards
(143 cards)
1
Q
which eye conditions come with red eyes?
A
conjunctivitis (pink eye), episcleritis, scleritis, uveitis, and keratitis
2
Q
what is the mechanism behind red eyes?
A
Hyperemia: Increased blood flow in the conjunctival, ciliary, or episcleral vessels, which can make the vessels more visible and give the eye a red appearance.
Erythema: Redness of the eyelids due to inflammation or infection.
Subconjunctival Hemorrhage: A break in a small blood vessel causing blood to collect under the conjunctiva, leading to a bright red patch on the sclera.
3
Q
what are some differential diagnoses for red eyes?
A
conjunctivitis, corneal disorders, [closed-angle] acute glaucoma, and acute uveitis.
4
Q
what are some things that can cause ocular pain?
A
Can be caused by
trauma to the eye, which could involve a direct injury.
Infections, such as conjunctivitis or keratitis, can cause pain due to inflammation and irritation of the eye tissues.
Inflammation of the eye’s internal structures, such as uveitis, can lead to discomfort.
Increased intraocular pressure (IOP), as seen in conditions like glaucoma, can also result in ocular pain.
5
Q
What causes foreign body sensation?
A
This sensation often results from the presence of actual foreign bodies in the cornea or conjunctiva, such as dust or eyelashes.
Any disturbance to the corneal epithelium, such as abrasions or erosions, can create a feeling as if something is in the eye.
Trichiasis, a condition where eyelashes grow inward and rub against the cornea, can also give a foreign body sensation.
6
Q
what are some conditions that cause photophobia (light sensitivity)?
A
Often caused by corneal inflammation (keratitis) or inflammation of the iris (anterior uveitis or iritis), which makes the eye sensitive to light.
Other systemic conditions like albinism (lack of pigment in the eyes) and aniridia (absence of the iris) can contribute to light sensitivity.
Systemic infections that induce fever can also cause photophobia.
7
Q
What is itchy eyes normally associated with?
A
Typically associated with allergic reactions in the eye, such as allergic conjunctivitis.
8
Q
what is scratching and burning eyes normally associated with?
A
These symptoms are commonly due to dryness of the eye, which can result from reduced tear production (lacrimal gland hypofunction). This can be a primary condition or secondary to systemic disorders like Sjögren’s syndrome.
Certain medications, including atropine-like drugs, can reduce tear production, leading to dryness.
Ocular surface diseases or simply being in a dry environment can also cause these sensations.
9
Q
what typically causes watery eyes?
A
Can occur when there is an obstruction in the tear drainage system, preventing tears from draining properly, which causes them to overflow onto the cheeks.
Malposition of the lower eyelid, such as ectropion (outward turning of the eyelid), can lead to inadequate tear drainage.
Reflex tearing can happen as a protective response to any irritation or disturbance of the corneal epithelium, even if the eye is generally dry.
10
Q
what is conjunctivitis and what are the common forms of it?
A
Conjunctivitis: This is an inflammation or swelling of the conjunctiva, the thin transparent layer of tissue that lines the inner surface of the eyelid and covers the white part of the eye. Conjunctivitis can be due to:
Bacterial infection: Often marked by yellow-green discharge, can be contagious, and typically treated with antibiotic eye drops.
Viral infection: Often associated with a cold or respiratory tract infection and is highly contagious.
Fungal infection: Less common and can occur after an eye injury involving plant material.
Allergic (non-infectious): Triggered by allergens like pollen, dust mites, or pet dander; characterized by itching, redness, and tearing, often seasonal.
11
Q
what is hordeolum and where is it located?
A
Hordeolum (Stye): An infection of the oil glands (meibomian gland) in the eyelid, leading to a painful lump on the edge or inside of the eyelid.
12
Q
what is dacryoadenitis?
A
Dacryoadenitis: Inflammation of the lacrimal gland, which can cause swelling and pain in the upper outer region of the eye.
13
Q
what is dacryocystitis?
A
Dacryocystitis: Infection of the lacrimal sac, leading to pain, redness, and swelling in the inner corner of the eye.
14
Q
what is A serious infection that affects the tissues around the eye, leading to painful swelling of the upper and lower eyelid, and possibly the eyebrow and cheek. It can cause the eye to protrude or bulge out and may lead to vision problems if not treated promptly?
A
orbital cellulitis
15
Q
what is Also known as preseptal cellulitis, this is an infection of the eyelid or skin around the eye. Unlike orbital cellulitis, it does not affect the eye itself?
A
periorbital cellulitis
16
Q
what is A chronic infectious disease caused by Chlamydia trachomatis, leading to a roughening of the inner surface of the eyelids. This can cause pain in the eyes and can lead to blindness if untreated?
A
Trachoma
17
Q
what are some eye conditions caused by infection?
A
Conjunctivitis (bacterial, viral, fungal; there is also allergic [non-infectious or irritative conjunctivitis]).
Hordeolum: infection of eyelid margin (follicles, or meibomian glands).
Dacryoadenitis (infection of lachrymal gland) & dacryocystitis (infection of lachrymal sac).
Orbital cellulitis
Periorbital cellulitis
Trachoma
HIV-related (due to weakened immune system)
18
Q
what is the most infectious form of conjunctivitis?
A
viral conjunctivitis
19
Q
what virus is viral conjunctivitis caused by?
A
adenovirus
20
Q
what are the symptoms of viral conjunctivitis?
A
Symptoms can include redness, a watery discharge, and a feeling of grittiness or irritation in the eye. It can be highly contagious and is known for its rapid spread, especially in communal environments.
21
Q
what are some other viruses that causes viral conjunctivitis?
A
Other viruses such as Herpes Simplex Virus (HSV), Varicella-Zoster Virus (VZV), and Molluscum Contagiosum can also cause viral conjunctivitis.
22
Q
what are the main symptoms of bacterial conjunctivitis?
A
Caused by bacterial infections, the primary symptom is a sticky, yellow or greenish-yellow eye discharge that may cause the eyelids to stick together, especially after sleep.
23
Q
which bacteria commonly causes bacterial conjunctivitis?
A
Common causative bacteria include Staphylococcus species, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis.
Neisseria gonorrhoeae and Chlamydia trachomatis can cause more severe, hyperacute forms of conjunctivitis.
24
Q
what eye condition is Triggered by allergens such as pollen, dust mites, or pet dander, this type of conjunctivitis is characterized by intense itching, tearing, and often a mucoid discharge. It is usually bilateral and can be associated with other signs of allergy like sneezing and an itchy nose?
A
allergic conjunctivitis
25
what type of conjunctivitis is less common and can be caused by a few specific types of viruses like enteroviruses. It is characterized by sudden onset of severe pain and bleeding underneath the conjunctiva leading to a red eye?
Hemorrhagic conjunctivitis
26
what type of conjunctivitis Occurs in newborns and can be caused by various agents, including bacteria acquired during passage through the birth canal. It can lead to serious eye damage if not treated promptly and appropriately?
neonatal conjunctivitis
27
what type of conjunctivitis is Often associated with long-term contact lens wear, it is believed to be a hypersensitivity response involving large papillae forming on the inner surface of the eyelids?
Giant papillary Conjunctivitis
28
What type of acute conjunctivitis is often associated with systemic symptoms such as fever and upper respiratory tract infection?
Viral conjunctivitis may be associated with systemic symptoms such as fever, adenopathy (enlarged lymph nodes), and upper respiratory tract infection as part of a viral prodrome.
29
Which form of acute conjunctivitis typically presents with purulent discharge that recurs at the lid margins and corners of the eye?
Bacterial conjunctivitis typically presents with purulent discharge, which may be yellow, white, or green, and tends to recur at the lid margins and corners of the eye shortly after wiping.
30
In the case of allergic conjunctivitis, what are some of the other symptoms that accompany the ocular symptoms?
Allergic conjunctivitis is often accompanied by nasal symptoms such as congestion, sneezing, and wheezing.
31
Which type of conjunctivitis is characterized by a watery discharge with strands of mucus?
Viral conjunctivitis is characterized by a watery discharge that may contain strands of mucus.
32
What symptom is primarily reported by patients with allergic conjunctivitis?
The primary complaint in allergic conjunctivitis is itching, which can be quite intense.
33
If a patient presents with pink or red conjunctiva and no itching, what type of acute conjunctivitis might they have?
The patient might have bacterial or viral conjunctivitis, as itching is typically limited to none in these types, unlike in allergic conjunctivitis where itching is a primary symptom.
34
what causes anterior blepharitis?
bacterial infection (staphylococcal blepharitis) or dandruff of the scalp and eyebrows (seborrheic blepharitis).
Occurs at the outside front edge of the eyelid where the eyelashes are attached.
Can be caused by bacterial infection (staphylococcal blepharitis) or dandruff of the scalp and eyebrows (seborrheic blepharitis). These conditions can also occur together and are not mutually exclusive.
Staphylococcal blepharitis is usually marked by red, swollen eyelids, and it may result in eyelash loss or dandruff-like scales around the base of the eyelashes.
Seborrheic blepharitis is less severe in terms of eyelid inflammation but causes greasy flakes or scales around the base of the eyelashes.
35
which form of blepharitis affect the meibomian gland? anterior or posterior
Posterior Blepharitis: Affects the inner edge of the eyelid that comes in contact with the eyeball.
It is caused by problems with the oil (Meibomian) glands in this part of the eyelid, which can become clogged.
Posterior blepharitis can lead to a more significant and chronic inflammation, impacting the eye surface and causing discomfort.
36
what is blepharitis?
Blepharitis is an inflammation of the eyelids that often affects the part of the eyelid where the eyelashes grow. It usually involves the part of the eyelid where the eyelashes grow and typically occurs when tiny oil glands located near the base of the eyelashes become clogged, leading to irritated and red eyes. Common symptoms include eyelid irritation, redness, a gritty sensation in the eye, and dandruff-like scales on the eyelashes.
37
what is hordeolum?
A hordeolum, commonly known as a stye, is an acute, localized infection or inflammation of the eyelid margin. It is typically caused by a bacterial infection.
38
which bacteria typically causes hordeolum?
Staphylococcus species
39
Is this internal or external hordeolum?
an infection of the meibomian glands, which are located within the eyelids and produce a lipid-rich secretion that contributes to the tear film. An internal hordeolum may be less visible on external examination but can cause a swollen eyelid and pain.
internal
40
Is this internal or external hordeolum?
This is an infection of the glands of Zeis or the glands of Moll. These glands are associated with eyelash follicles and are responsible for the secretion of substances that help lubricate the eyelash. An external hordeolum presents as a painful, red, swollen nodule at the eyelid margin.
external
41
which hordeolum affects the Zeis and Moll gland?
external
42
how are hordeolum formed?
first secretion from eyelid oil glands (zeis and meibomian) thickens (inspissation) and then becomes stagnant (stasis) creating environment for bacteria (mainly staphylococcus aureus) leading to secondary infection. The body's immune system responds by sending polymorphonuclear leukocytes to the site which together with death of some of the infected tissue (necrosis) form an abscess creating the painful, red, warm. swollen lump on eyelid.
They can cause blurry vision due to putting pressure on the cornea temporarily changing its shape. They can rupture on their own or with treatment.
43
how does hordeolum cause blurry vision?
They can cause blurry vision due to putting pressure on the cornea temporarily changing its shape. They can rupture on their own or with treatment.
44
what is the most common inflammatory lesion of the eyelid?
chalazion
45
what is chalazion?
Slowly enlarging eyelid nodules, formed by inflammation and obstruction of sebaceous glands either meibomian or zeis and moll.
46
which eyelid gland is deeper, meibomian or zeis and moll?
meibomian
47
what triggers the granulomatous inflammatory response?
when lipid breakdown products, possibly from bacterial enzymes or the glands' retained secretions, leak into the surrounding tissue.
48
what conditions trigger chalazion when they affect eyelid oil glands?
These include seborrheic dermatitis, acne rosacea, chronic blepharitis, high blood lipid levels, immunodeficiency states, viral infections, and possibly stress and carcinoma, although the causality and mechanisms for these are not fully understood or proven.
49
what form on eyelid as a result of gland obstruction and sterile inflammation rather than infection?
chalazia
hordeolum forms from infection and can develop into painless chalazia
50
what eye condition is a mass of granulation tissue and chronic inflammation (with lymphocytes and lipid-laden macrophages)?
chalazia
51
what eye condition is an acute pyogenic inflammation with polymorphonuclear leukocytes (PMNs) and necrosis with pustule formation?
Hordeolum
52
what tend to be larger, less painful and have a less acute presentation than hordeola?
chalazia
53
which eye condition involves Infection of dermis and subcutaneous periorbital tissues (aka, pre-septal cellulitis).
Microorganisms enter through local breaks of skin after abrasions, burns, insect bites (most common Staph. aureus or Strep. pyogenes)?
Periorbital cellulitis
54
what organism spreads hematogenously from sites of infection like sinusitis or otitis media in periorbital cellulitis?
Streptococcus pneumoniae and Moraxella catarrhalis.
55
what other infections can organisms spread from to periorbital cellulitis?
dacryoadenitis (inflammation of the lacrimal gland), dacryocystitis (inflammation of the lacrimal sac), hordeolum (stye), acute chalazion (a blocked oil gland in the eyelid), or conjunctivitis (inflammation of the conjunctiva).
56
what are some clinical presentations of periorbital cellulitis?
Patients with periorbital cellulitis often present with tenderness, induration (hardening of the tissue), warmth, and swelling of the eyelid and surrounding periorbital area.
57
what can periorbital cellulitis develop into if it moves beyond the orbital septum?
If the infection spreads posteriorly beyond the orbital septum, it can lead to orbital cellulitis, a more serious condition that can affect vision and eye movements.
58
what is orbital cellulitis?
Pathogenesis: Orbital cellulitis occurs when pathogens (usually bacteria) breach the orbital septum, which is a membrane that separates the anterior aspect of the eyelid from the posterior aspect containing the eyeball and its associated muscles and nerves.
58
what is a more serious condition than periorbital cellulitis that can affect vision and eye movements and pupillary reflex?
orbital cellulitis
58
what's the difference between periorbital cellulitis and orbital cellulitis?
Periorbital cellulitis has normal visual acuity, eye movements & pupillary reflexes (these are abnormal in orbital cellulitis).
59
what are the local signs of orbital cellulitis?
Conjunctival chemosis: This refers to the swelling (edema) of the conjunctiva, which is the clear membrane covering the white part of the eye.
Eyelid and periorbital edema: Swelling around the eye and eyelids.
Pain, tenderness, induration, warmth: These are classic signs of inflammation and infection.
59
what is conjunctival chemosis?
Conjunctival chemosis: This refers to the swelling (edema) of the conjunctiva, which is the clear membrane covering the white part of the eye.
60
what are other signs of orbital conjunctivitis that indicates orbital tissue involvement?
Impinged extraocular muscles: The infection can cause the muscles that move the eye to become swollen and painful, leading to restricted movement (ophthalmoplegia).
Impinged nerves: The swelling can also affect the nerves, leading to an afferent pupillary defect (which affects the reaction of the pupils to light) and decreased visual acuity.
Proptosis: The eye may bulge out (proptosis) due to the swelling of the tissues behind the eye, leading to potential drying and scarring of the cornea.
61
what are some complications that can arise from not treating orbital cellulitis soon enough?
Complications: If not treated promptly, the infection can spread, leading to:
Endophthalmitis: Inflammation within the eye.
Panthophthalmitis: Inflammation of all eye layers.
Subperiosteal abscess: A collection of pus that forms under the periosteum, which is the dense layer of connective tissue covering bones.
Brain abscess: A collection of pus that develops in the brain due to the infection.
Cavernous sinus thrombosis: A blood clot within the cavernous sinus, which is a large channel of venous blood situated at the base of the brain.
Meningitis: Inflammation of the membranes covering the brain and spinal cord.
Orbital abscess: A pocket of infection within the orbit itself.
62
what is endophthalmitis?
Endophthalmitis: Inflammation within the eye.
63
what is panthophthalmitis?
Panthophthalmitis: Inflammation of all eye layers.
64
what is subperiosteal abscess?
Subperiosteal abscess: A collection of pus that forms under the periosteum, which is the dense layer of connective tissue covering bones.
65
what are some common causes of visual field loss?
Common Causes of Visual Impairment:
Cataracts: Clouding of the eye's lens, leading to a decrease in vision.
Tumors: Abnormal growths that can put pressure on or damage visual pathways.
Vascular lesions: Abnormalities in the blood vessels of the eye or brain that can affect vision.
Demyelinating disorders: Conditions like multiple sclerosis that cause damage to the protective covering (myelin sheath) of nerve fibers in the eyes and brain, affecting the transmission of visual signals.
Neurologic impairment: Damage to the retina, optic nerve, or visual cortex in the brain can disrupt the normal visual process.
66
what are scotomas?
Scotomas:
These are partial loss of vision or blind spots in an otherwise normal visual field. They are often found to be unilateral (affecting one eye)
67
what are some causes for scotomas?
Multiple sclerosis: A disease that can damage the myelin sheath in the central nervous system.
Macular degeneration: A disease that deteriorates the central portion of the retina.
Hypertensive or diabetic retinopathy: Damage to the retina's blood vessels due to high blood pressure or diabetes.
Methyl alcohol poisoning: Toxicity from methyl alcohol can lead to vision loss.
Strokes: Interruption of blood supply to the brain can affect visual pathways.
68
what is hemianopsia?
Hemianopsia:
This is a blindness or reduced vision in half of the visual field.
69
what is bitemporal hemianopsia and which part of the vision neural pathway is affected by lesion?
Bitemporal hemianopsia: Loss of vision from both outer (temporal) fields occurs with lesions to the optic chiasm, where the optic nerves partially cross over.
70
what is homonymous hemianopsia and which part of the vision neural pathway is affected by lesion?
Homonymous hemianopsia: Loss of vision that is the same [side] in both eyes, either the right or left halves, occurs with lesions behind the optic chiasm such as damage to the optic tract, radiation of fibers from the optic tract to the visual cortex, or the visual cortex itself.
71
What visual field defect is characterized by a loss of vision in the outer halves of both visual fields?
Bitemporal hemianopia is characterized by the loss of the outer (temporal) halves of the visual field in both eyes. This usually results from a lesion at the optic chiasm, often due to a pituitary tumor compressing the crossing fibers from the nasal retina of both eyes.
72
What does left nasal hemianopia suggest about the location of the lesion in the visual pathway?
Left nasal hemianopia suggests a lesion that affects the temporal fibers of the right eye, which could indicate damage to the peripheral part of the right optic nerve before it reaches the optic chiasm.
73
Where is the lesion likely located if a patient presents with right homonymous hemianopia?
Right homonymous hemianopia indicates a loss of the right visual field in both eyes and suggests a lesion in the left optic tract, the left lateral geniculate nucleus, or the left visual radiation.
74
If a patient has left homonymous hemianopia with macular sparing, what does this imply?
Left homonymous hemianopia with macular sparing indicates a loss of the left visual field in both eyes, sparing the central vision. This typically implies a lesion in the visual cortex of the right occipital lobe. The macula has a dual blood supply from both the middle cerebral artery and the posterior cerebral artery, which often allows it to be spared in occipital lobe strokes.
75
What condition might cause a bitemporal hemianopia?
A bitemporal hemianopia is commonly caused by a lesion that compresses the optic chiasm from below, such as a pituitary adenoma.
76
what is cataract?
A cataract is the clouding or opacification of the eye's lens, which can lead to a decrease in vision. It is a common condition, especially as people age.
77
what are some risk factors for cataract?
Congenital: Some babies are born with cataracts or develop them in childhood, often in both eyes. These may be the result of genetic issues or congenital infections.
Age (Senile Cataracts): The most common type of cataract is related to aging of the eye. [Stiffening of lens.]
Systemic Diseases: Conditions such as diabetes can lead to cataract development. In diabetics, high blood sugar levels cause glucose to accumulate in the lens, and through a process called glycosylation, sorbitol is produced, which can increase osmotic pressure inside the lens and lead to water accumulation (overhydration) in the lens, causing cloudiness.
Trauma: Injury to the eye, whether blunt or penetrating, can cause cataracts. Traumatic cataracts may develop immediately after the injury or years later.
Previous Eye Surgery: Eye surgery can lead to cataract formation later on.
High Myopia: People with severe nearsightedness have a greater risk of developing cataracts.
Retinitis Pigmentosa: This is a group of genetic disorders that affect the retina's ability to respond to light. People with this condition have a higher risk of cataracts.
Acute Angle-Closure Glaucoma: This type of glaucoma can lead to rapid cataract development due to the increased pressure within the eye.
Exposure to Toxins: Certain toxins, including UV radiation from sunlight, can accelerate the denaturation of lens proteins, leading to cataract formation.
78
what are some symptoms of cataract altered lens scattering light?
Scattering of Light: The altered structure of the lens scatters incoming light, leading to symptoms such as:
Blurred Vision: The inability to see fine details.
Decreased Contrast Sensitivity: Difficulty in distinguishing between shades of light and dark.
Increased Refractive Power and
Nearsightedness: Alteration in the lens's ability to focus light, often resulting in a shift toward nearsightedness (myopia).
Glare and Halos Around Lights: Challenges with bright lights, which can cause problems with activities like nighttime driving.
79
what are some complications of cataract lens as it becomes more enlarged and dense?
Complications: If the cataract becomes very dense or enlarged (hyper mature), it can lead to complications such as:
Contact with Trabecular Meshwork: The enlarged lens may come into contact with the drainage pathways of the eye, namely the trabecular meshwork.
Secondary Angle Closure Glaucoma: This contact can block the outflow of aqueous humor, the fluid inside the eye, leading to increased intraocular pressure, which is a hallmark of angle closure glaucoma. This condition requires urgent medical attention to prevent permanent vision loss.
80
what is corneal abrasion?
A corneal abrasion refers to a scratch or disruption of the cornea's outermost layer, the epithelium. This condition can be quite painful and is often accompanied by other symptoms.
81
what are some risk factors for corneal abrasion?
Risk Factors:
Foreign bodies, such as dust or metal particles, can cause abrasions if they come into contact with the cornea.
Incomplete closure of the eyelid, which can occur with Bell's palsy, leaves the cornea unprotected and more susceptible to abrasion.
Trichiasis, a condition where eyelashes grow inward, can scratch the cornea.
Contact lenses, especially if they are poorly fitted or overworn, can cause mechanical trauma to the cornea.
Impairment of the trigeminal nerve, as can occur with herpes zoster (shingles), infections, diabetes, certain medications, or after surgery, may lead to corneal abrasions due to decreased corneal sensitivity and protective reflexes.
82
how does contact lens cause corneal abrasion?
Contact Lenses:
Mechanical trauma to the cornea can occur from the contact lenses themselves, either from overuse or if they are too tight.
Contact lenses can reduce the amount of oxygen that reaches the cornea, which can cause the epithelium to stick to the lens and be removed upon lens extraction, leading to an abrasion.
83
how does neurotrophic keratopathy contribute to corneal abrasion?
Neurotrophic Keratopathy:
This condition arises secondary to reduced corneal innervation and is characterized by a decrease in corneal sensitivity.
The reduced sensation leads to an impaired tearing reflex, causing dryness and a loss of lubrication.
Reduced blinking and reduced adhesion between the corneal epithelium and Bowman’s layer result in a loss of structural integrity of the cornea.
84
what happens if the corneal abrasion goes deep enough to affect the anterior chamber?
Damage to Anterior Chamber:
If the abrasion is deep enough to affect the anterior chamber, it can lead to uveitis (inflammation of the middle layer of the eye) and photophobia due to irritation of the ciliary muscle.
85
what is the most prominent symptom of corneal abrasion?
pain
typically relieved to some extent by topical anesthesia.
86
what are other symptoms of corneal abrasion besides pain?
foreign body sensation, photophobia, tearing, redness
87
what typically presents with the disruption of the cornea's outer layer, the epithelium, and often involves the deeper layer, the stroma. This condition is associated with inflammation, which can be due to infectious or noninfectious causes?
corneal ulcer
88
what are the infectious causes of corneal ulcers?
Infectious Causes:
Bacterial: Common in contact lens wearers or after eye trauma.
Fungal: Often result from an injury involving plant material or in immunocompromised individuals.
Herpes (simplex and zoster): Viral infections that can recur and cause inflammation and ulceration.
Acanthamoeba: A serious infection often associated with contact lens misuse, particularly when lenses are exposed to water.
89
what are the noninfectious causes of corneal ulcers?
Noninfectious Causes:
Chemicals: Such as acids or alkalis, causing burns and subsequent ulcers.
Burns: Thermal or ultraviolet burns can damage the cornea.
Sicca (Sjogren syndrome): An autoimmune condition leading to dry eyes, which can predispose to ulceration.
Vitamin A Deficiency: Essential for maintaining the health of epithelial tissues, its deficiency can lead to ulceration.
Eye Drops: Some medications can cause corneal inflammation and ulceration as a side effect.
90
what are the immune-related causes?
Immune-Related Causes:
Wegener Granulomatosis: An autoimmune disorder that can cause granulomas and vasculitis.
Rheumatoid Arthritis: A chronic inflammatory disorder that can also affect the eyes.
Collagen Vascular Diseases: These systemic conditions can involve the eye and lead to ulceration.
91
what is the mechanism behind the immune-related causes?
Immune-Related Mechanisms:
In genetically predisposed individuals, immunologic responses to unknown antigens can lead to the development of corneal ulcers.
Defective function of suppressor T-lymphocytes and the production of autoantibodies, such as antinuclear antibodies, contribute to the development of ulcers.
Activation of the complement pathway, part of the immune system, can also cause inflammation leading to ulceration.
The exact pathogenesis of corneal ulcers depends on the etiologic agent, whether it's an infection, a chemical burn, or an autoimmune response.
92
what is a group of eye diseases that are traditionally characterized by elevated intraocular pressure (IOP), which can lead to damage to the optic nerve. Over time, if the condition is not properly managed, it can result in vision loss?
Glaucoma (aka optic neuropathy)
93
what is the most common form of glaucoma. It occurs when the eye's drainage canals become slightly clogged over time, leading to increased eye pressure. It develops slowly and is a lifelong condition?
open-angle glaucoma
94
why is open angle glaucoma called open angle?
The "open-angle" refers to the angle between the iris and cornea, which is as wide as it should be, but the eye's drainage canals become blocked over time.
95
what form of glaucoma is less common and can occur suddenly, which is a medical emergency. It happens when the iris is too close to the drainage canal (trabecular meshwork), which can get completely blocked suddenly, causing a rapid increase in intraocular pressure?
closed-angle glaucoma (aka narrow angle glaucoma)
96
what is mixed glaucoma?
This refers to cases where both mechanisms are present. A person with open-angle glaucoma can also have episodes of angle-closure, leading to a mixed picture. This might require different management strategies to address the dual mechanisms contributing to optic nerve damage.
97
what is an ophthalmologic emergency and should be ruled out in acutely ill patients with red eye & colored halos around bright light?
angle-closure glaucoma
98
what are the risk factors for angle-closure glaucoma?
Risk Factors for Angle-Closure Glaucoma:
Age: The risk increases with age.
Gender: Females are more likely to develop angle-closure glaucoma.
Ethnicity: It is more common in Asians compared to other ethnic groups and is a significant cause of blindness among African Americans. The text also notes it is three times more frequent in Blacks compared to Whites, though it typically refers to open-angle glaucoma, which is the more common form of glaucoma in African Americans.
Family History: Having a family history of glaucoma, especially in first-degree relatives, increases the risk.
Anatomical Factors: Individuals with hyperopia (farsightedness) are at a higher risk because they tend to have shallower anterior chambers and narrower angles, which can predispose to angle closure. Severe myopia (nearsightedness) is also listed, though it is more commonly associated with open-angle glaucoma.
Systemic Conditions: Hypertension, diabetes, and hypothyroidism are systemic conditions that can be associated with an increased risk of glaucoma.
Elevated IOP: While elevated IOP is a risk factor, it is also a consequence of the angle closure.
99
what are symptoms of angle closure glaucoma?
Symptoms of Acute Angle-Closure Glaucoma:
Red Eye: The eye may become red due to the sudden increase in IOP and inflammation.
Colored Halos Around Bright Lights: Patients may report seeing halos around lights due to corneal edema caused by the elevated IOP.
Pain: The condition can be very painful due to the rapid increase in IOP.
Visual Disturbance: There may be a sudden decrease in vision.
Nausea and Vomiting: These symptoms can accompany the eye pain and redness.
100
which glaucoma is painful and more sudden? closed or open-angle?
closed-angle glaucoma
101
what eye anatomical factors contribute to increasing IOP and closure of iridocorneal angle?
Certain anatomical features of the eye, such as a thinner ciliary body, shallow anterior chamber, and a smaller overall axial length of the eye can lead to crowding of the ocular structures.
This crowding can increase resistance to the outflow of aqueous humor, which is the fluid produced inside the eye.
Increased resistance to outflow leads to increased intraocular pressure (IOP), which in turn can push the iris forward.
The forward movement of the iris can cause the closure of the iridocorneal angle, which is where the aqueous humor normally drains from the eye.
102
what causes edema and clouding of posterior cornea and why?
Aqueous Humor Stasis:
If aqueous humor flow is blocked, the cornea can become deprived of nutrients and oxygen, leading to edema (swelling) and clouding of the posterior cornea due to hypoxemia (low levels of oxygen).
103
how does scotoma happens in glaucoma and how does it affect vision?
Mechanical Damage:
Increased IOP, particularly when it rises abruptly, can cause mechanical damage to the optic nerve axons, leading to scotomas (blind spots).
These scotomas are usually not central but can cause photophobia (light sensitivity) and vision loss.
104
what is anterior synechiae and what does it do in eye?
Anterior Synechiae Formation:
Anterior synechiae are adhesions of the iris to the cornea, which can block aqueous humor outflow further.
Glaucoma, which is a group of eye conditions that lead to damage to the optic nerve, can cause synechiae, and conversely, synechiae, particularly from other causes like uveitis (inflammation of the middle layer of the eye), can also lead to glaucoma.
105
what can cause synechiae and be caused by synechiae?
glaucoma
106
what inflammatory eye condition can cause synechiae?
uveitis
107
how is synechiae formed?
The formation of synechiae involves the deposition of inflammatory cells, fibrin, and proteins which stimulate the formation of adhesions between ocular structures, leading to fibrosis or scarring.
108
what is posterior synechiae and what does it do?
Adhesions between the iris and the lens, known as posterior synechiae, can block the flow of aqueous humor from the posterior chamber to the anterior chamber of the eye, potentially leading to secondary glaucoma.
109
what is known as normal tension glaucoma?
it's important to note that POAG (primary open angle glaucoma) can occur even when IOP is within the normal range, a situation sometimes referred to as normal tension glaucoma.
110
what is associated with progressive loss of peripheral vision, which can eventually lead to loss of central vision if the condition (POAG) is not treated effectively?
cupping
In POAG, the optic nerve damage is often indicated by a particular appearance of the optic disc known as "cupping," where there is an increased cup-to-disc ratio due to the loss of neuroretinal tissue at the optic disc.
111
which glaucoma is the most common in the USA and called the "sneak thief of sight"?
POAG is the most common form of glaucoma in the United States and affects approximately 2% of the population over the age of 40. It's often called the "sneak thief of sight" because it typically doesn't have symptoms in its early stages and the loss of vision is gradual. Many individuals do not realize they have the condition until significant vision is lost.
112
why is Primary Open Angle Glaucoma called the sneak thief of sight?
It's often called the "sneak thief of sight" because it typically doesn't have symptoms in its early stages and the loss of vision is gradual. Many individuals do not realize they have the condition until significant vision is lost.
113
which glaucoma is Second most common cause of blindness worldwide?
POAG
114
what does cupping of the optic nerve mean?
Cupping of the Optic Nerve Head: As the nerve fibers are lost, the optic disc begins to hollow out or "cup," which is a classic sign of glaucoma observed during an eye exam.
115
how does primary open angle glaucoma gradually develop?
Optic Nerve Axon Loss: This is the fundamental pathological change in glaucoma, where the axons of the retinal ganglion cells are progressively damaged and lost.
Ganglion Cell Susceptibility: The retinal ganglion cells are sensitive to damage due to various factors, which may include genetic predisposition, age, and elevated intraocular pressure (IOP).
Microcirculatory Deficiency: The optic nerve head (the front part of the optic nerve, also known as the optic disc) may experience reduced blood flow or microcirculatory problems, depriving the nerve fibers of essential nutrients and oxygen.
Extracellular Matrix Factors: Changes in the extracellular matrix around the optic nerve head may contribute to the susceptibility of the optic nerve to damage. These changes may affect the support and nutrition of the optic nerve fibers.
Cupping of the Optic Nerve Head: As the nerve fibers are lost, the optic disc begins to hollow out or "cup," which is a classic sign of glaucoma observed during an eye exam.
116
what causes primary open angle glaucoma?
Primary Open-Angle Glaucoma: The exact cause is often unclear, but it's believed to be related to genetic factors combined with environmental influences.
117
what is secondary open angle glaucoma and what causes it?
Secondary Open-Angle Glaucoma: This form of glaucoma is due to identifiable causes, which may include:
Neovascularization: Often associated with diabetes mellitus, new, abnormal blood vessels grow on the iris and the trabecular meshwork, blocking the drainage of aqueous humor.
Debris: Accumulation of debris such as red blood cells (RBCs), white blood cells (WBCs), or flaked off material from the lens or iris (pseudoexfoliation) can clog the drainage system.
Corticosteroids: Long-term use of corticosteroids can increase IOP, leading to glaucoma.
Retinal Detachment: This can also be associated with changes in the eye that affect intraocular fluid dynamics.
118
which glaucoma is often asymptomatic until the disease has progressed significantly. This is because the initial loss of peripheral vision can be very subtle and go unnoticed by the patient until the central vision is affected. The mean progression rate from a full field of vision to blindness in untreated takes approximately 25 years?
POAG
119
what does it mean as cup to disk ratio increases?
The higher the cup-to-disc ratio, the more significant the loss of nerve fibers and the more advanced the glaucoma.
The cup-to-disc ratio is a measurement used to assess the optic nerve for glaucoma damage. The optic disc is where the optic nerve enters the eye, and the cup is the central depression within the disc where the nerve fibers pass.
A) 0.2: Indicates a healthy optic nerve with a small cup compared to the disc size.
B) 0.5: Shows a moderate cupping, which may be normal for some individuals but can also indicate early glaucomatous changes.
C) 0.7 and D) 0.9: These ratios indicate advanced cupping consistent with glaucoma. The higher the cup-to-disc ratio, the more significant the loss of nerve fibers and the more advanced the glaucoma.
120
what is age related macular degeneration?
Age-related macular degeneration (AMD) is a common eye condition and a leading cause of vision loss among people age 50 and older. It damages the macula, which is a small spot near the center of the retina and the part of the eye needed for sharp, central vision, which lets us see objects that are straight ahead. central vision (required for driving, reading, watching television, and performing activities of daily living.)
121
which age related macular degeneration is characterized by the presence of drusen, yellow deposits that form under the retina. It is the most common type of AMD and tends to progress more slowly. Over time, the macula may become thinner and lose function? Wet or dry?
dry
Pathogenesis of dry AMD is unclear.
abnormalities in components of Bruch's membrane (a layer in retina); inflammation and chronic infection play a role.
122
which age related macular degeneration is Also known as neovascular or exudative AMD, this type is less common but more serious. It can lead to more rapid vision loss. It occurs when new, abnormal blood vessels grow under the retina (choroidal neovascularization), which can leak fluid or blood. This leakage can cause scarring of the macula and loss of central vision?
wet
there is also retinal and choroidal neovascularization and ischemic retinopathy due to vascular endothelial growth factor (VEGF).
123
which signaling protein is responsible for growth of abnormal eye vessels in wet age related macular degeneration?
The growth of these abnormal vessels is stimulated by vascular endothelial growth factor (VEGF), and the current treatments for wet AMD primarily involve therapies that inhibit VEGF.
124
which age related macular degeneration is Asymptomatic in Early Stages: often has no symptoms in the early stages.
Gradual Loss of Vision: As the condition progresses, there may be a slow decline in central vision in one or both eyes.
Difficulty with Fine Tasks: Patients may notice difficulty performing tasks that require sharp central vision, such as reading, driving, or recognizing faces.
Scotomas: These are areas of partial alteration in the field of vision consisting of a spot or partial shadow.
Need for More Light: Individuals with this may find they need brighter lighting when doing close work.
dry AMD
125
which age related macular degeneration presents Acute Symptoms: can lead to more rapid and severe symptoms than the other.
Visual Distortion: This can include a sudden distortion of vision where straight lines appear wavy or curved, known as metamorphopsia.
Loss of Central Vision: There can be a rapid loss of central vision due to bleeding or fluid leakage under the retina.
Subretinal Hemorrhage or Fluid Accumulation: This occurs as the abnormal blood vessels grow under the retina and macula, leading to bleeding and fluid leaks?
Wet AMD
126
which AMD has slower less severe symptoms and you notice you need brighter light?
dry AMD
this may also progress to the more severe wet AMD
127
which AMD suddenly presents wit metamorphopsia (straight lines suddenly appear wavy or curved)?
wet AMD
128
what is drusen and which AMD does it present in?
drusen, which are yellow deposits that accumulate under the retina. Drusen are composed of lipids, proteins, and extracellular waste material. Drusen is also Mixture of B amyloid, cholesterol and other proteins, lipids, calcium, zinc, iron, and phosphate.
Dry AMD
129
what is retinal detachment?
Retinal detachment is a serious condition where the neurosensory layer of the retina separates from the underlying retinal pigment epithelium (RPE) and choroid. There are three primary types of retinal detachment, each with distinct mechanisms and risk factors:
Tractional retinal detachment, exudative retinal detachment, and rhegmatogenous retinal detachment.
130
what is tractional retinal detachment?
Tractional Retinal Detachment:
This type occurs when fibrous or fibrovascular tissue, which can develop due to conditions like proliferative diabetic retinopathy, exerts traction on the retina.
The traction can mechanically pull the retina away from the underlying layers without causing a tear.
Common risk factors include ocular trauma, neovascularization often secondary to diabetes, and other retinal diseases such as macular degeneration.
131
what are common risk factors for tractional retinal detachment?
Common risk factors include ocular trauma, neovascularization often secondary to diabetes, and other retinal diseases such as macular degeneration.
132
what is exudative retinal detachment?
Exudative Retinal Detachment:
In exudative (or serous) retinal detachment, fluid accumulates under the retina without the presence of a tear or break.
This can happen because of increased permeability of the retinal blood vessels due to vascular damage, inflammation, or infection, leading to fluid leaking into the subretinal space.
There is no retinal tear or vitreous traction involved in this type of detachment.
133
what is rhegmatogenous retinal detachment?
Rhegmatogenous Retinal Detachment:
The most common type of retinal detachment is rhegmatogenous, which is related to aging.
With age, the vitreous humor (the gel-like substance filling the eye) can liquefy and shrink, leading to vitreous detachment from the retina's surface.
If the vitreous is firmly attached to the retina in certain spots, this movement can create traction that leads to a retinal tear.
Once there is a tear, the liquid vitreous can pass through the tear and accumulate under the retina, causing it to detach from the underlying RPE (retinal pigment epithelium) and choroid.
134
what is the most common type of retinal detachment?
rhegmatogenous retinal detachment.
135
what symptom is common during early stages of retinal detachment and what causes it?
These are perceived flashes of light (photopsia) that can occur when the retina is being pulled or tugged, which is common in the early stages of retinal detachment. The traction on the retina stimulates it, leading to the sensation of flashing lights.
136
what causes photopsia in early retinal detachment?
The traction on the retina stimulates it, leading to the sensation of flashing lights.
137
floaters is another sign of retinal detachment, what are they?
Floaters:
Floaters are small moving spots or "cobwebs" in one's vision. In the context of retinal detachment, they can be caused by the release of pigment cells into the vitreous humor of the eye as the retina detaches.
138
what causes floaters?
they can be caused by the release of pigment cells into the vitreous humor of the eye as the retina detaches.
139
shafer's sign is another sign of retinal detachment, what is it?
Shafer’s sign: The presence of clumps of pigment cells in the anterior vitreous humor, which can be visualized with a slit lamp examination, is known as Shafer’s sign and is suggestive of a retinal tear or detachment.
140
what is described as a curtain falling over peripheral visual field?
retinal detachment visual field defect
this indicated decreased or loss vision that if left untreated will spread to central vision.
The visual field defect may be described by the patient as cloudy, irregular, or like a curtain falling across the field of vision.
