Flashcards in Lecture I Deck (63):
What is the order of the muscles around the eyes, going from the closest to the opening, outward?
What is the muscle that raises the eyelid?
Levator palpebrae superioris
What is the nerve that innervates the orbicularis oculi and pretarsal / preseptal muscles?
What is the innervation of the levator superioris muscle?
Which part of the ANS keeps the eye open? Through which CN does this occur?
SNS through CN 7
What is the septum that divides the deep part of the superior eye, from the superficial part?
What is Mueller's muscle? What is its main role?
Superior tarsal muscle that keeps the eye open
Entrapment of the orbicularis oculi 2/2 trauma usually occurs where?
In the maxillary sinus
What are the zonules of the eye?
Suspensory ligaments of the eye that attached the ciliary body to the lens
What is the effect of contraction of the ciliary muscle of the eye?
Lower tension on the lens = accommodation***
What is the choroid part of the eye?
Vascular part of the eye
What are the upper and lower punctum of the eye?
Upper and lower opening on the medial side of the eye that drain tears into the nose
What is the caruncle of the eye?
The red bit next to the nose
What do the upper and lower punctum drain into? What structures?
Upper and lower canaliculus into the lacrimal sac
What is the limbus of the eye?
The outer part of the iris
Where is the lacrimal gland relative to the eye?
What are the layers of the eye from superficial to deep? (5)
What determines damage to the cornea results in scarring or total regeneration?
If break through Bowman's layer, then will not
What keeps the fluid from passing into the cornea from the aqueous humor?
Na/K pump on the endothelial layer
What are the components of the uveal tract? (3)
What causes presbyopia?
Slow increased thickening of the cornea, that eventually causes a change in the shape of the cornea, and clouding
True or false: cataracts are a part of normal development of the eye
What part of the eye secretes the aqueous humor? What are the receptors that are located here?
Alpha 2, beta 1, beta 2
What are the receptors located on the ciliary muscle?
M3 and beta 2
What is the autonomic receptor located on the radial (dilator) muscle of the eye?
What is the autonomic receptor located on the sphincter (constrictor) muscle of the eye?
The choroid supplies what part of the eye?
Outer 2/3 of the retina
What supplies the inner 1/3 of the retina?
How does fluid drain from the eye?
Through the anterior chamber, into the trabecular network, and through the canal of schlemm
What, generally, is open-angled glaucoma?
Blockage of the canal of schlemm causes increased IOP
Why is there cupping of the optic disc with glaucoma?
Increased pressure in the anterior chamber is transmitted through the vitreous humor to the optic disc
What is the important ratio that is used to determine the severity of glaucoma?
What is the pattern of vision loss in the eye?
Upper outer quadrant-- upper temporal part
What is scotoma?
Reduced or absent vision
What is hemianopia?
Loss of half of a visual field
What is homonymous?
Either right or left visual field
What do the right and left optic radiations receive information from respectively?
Left radiation is from right eye to left brain
Right radiation is from left eye, right brain
A lesion to the optic nerve prior to the chiasm will result in what sort of blindness?
Total in one eye
A lesion to the optic nerve in the middle of the chiasm will result in what sort of blindness?
A lesion to an optic radiation will result in what sort of visual disturbance?
True or false: the optic nerve is a direct extension of the brain
What are the macula and the fovea?
Macula is the area of sharp, central vision, with the fovea within it as the area that has the highest density of color
Why aren't there vessels going into the macula?
Otherwise would have vessels covering vision
True or false: the relative pigmentation of the skin is reflected in the retina
What is the role of Rhodopsin?
a biological pigment found in the rods of the retina and is a G-protein-coupled receptor (GPCR). Rhodopsin is extremely sensitive to light, and thus enables vision in low-light conditions. When rhodopsin is exposed to light, it immediately photobleaches. In humans, it is regenerated fully in about 45 minutes
true or false: Only a small fraction of metabolism in the lens is directed toward maintaining the transparency of the lens
False-- metabolism is directed entirely toward it
Where in the lens does the majority of metabolism take place?
Glucose enters the lens from where?
What percent of glucose metabolism is in the lens? What happens in hyperglycemic states?
Shunted to this using aldose reductase
What is the consequence of sorbitol in the lens?
lens does not have the enzyme that is needed to break down sorbitol, so it builds up. Since it is osmotically active, the lens swells
What is sorbitol converted to once in the lens? How fast is this?
Patient with new onset blurred vision should be suspected of having what?
What happens if there is chronic swelling in the lens d/t DM?
Leads to cell rupture, causing a release of amino acids, K+ etc, which leads to cataract development
What are the two main refractive surfaces of the eye? What portion of refractive power comes from each of these?
What is astigmatism?
Refractive power of the cornea/lens is different in one meridian that another
What is accomodation?
The ability of the ciliary muscle to contract or relax that zonules, allowing the lens to focus near
What are the zonules of the eye?
a ring of fibrous strands connecting the ciliary body with the crystalline lens of the eye. These fibers are sometimes collectively referred to as the suspensory ligaments of the lens.
What is myopia? Hyperopia?
Myopia = nearsightedness (what you are)
Hyperopia = farsightedness
What happens to axial length with myopia and hyperopia?
Myopia = axial length too short
Hyperopia = axial length too long
When does presbyopia usually present?
Can you halt the progression of presbyopia?
What is the technical definition of legal blindness?