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what 5 things do you examine for for the optic nerve?

disc size, margins, contour of rim tissue, C/D ratio and rim tissue and NFL


what is a distinct margin?

easy to see the edges of the disc 360 - not uncommon for nasal to be indistinct and still be normal


what is an indistinct margin?

unable to see the edges of the disc for the majority of the ONH diameter


what is a normal and abnormal variation of an indistinct nerve?

normal = heaped up appearances or small congenital anomalous nerves
abnormal = papilledema


what is a malinserted disc?

congenital - disc is tilted along the vertical axis (appears to tilt upward nasally and down temporal, often has a scleral crescent)


what is a tilted disc?

congenital - the vertical axis is tilted, often downward nasally (often associated with tilted disc syndrome)


what 3 things can cause papilledema?

increased ICP due to brain lesion, idiopathic intracranial hypertension, and hypertensive crisis (bilateral)


what are 3 pseudopapilledemas (AKA congenital disc anomalies)?

optic nerve head drusen, congenitally full disc, and malinserted disc


when looking at a the ONH - how do you know if there is papilledema vs. pseudopapilledema?

if swollen (papilledema) - the view of the vessels will be obscured (like looking through a cloud)


what 5 signs point to papilledema?

indistinct margins, - SVP, + obscuration of vessels and hyperemic rim color


what information does the contour or "type" of ON rim provide?

contour provides information of the neuroretinal rim tissue, also helps to look for notching for glaucoma and vessel deflection


what are the 4 types of ONH contour?

flat, cylinder, slope/bowel, and hooked


what is the C/D and physiological cupping typically for a type 1 nerve (flat)?

C/D = 0-0.2
cupping = less than or equal to 1 diopter in depth


what is the C/D and physiological cupping typically for a type 2 nerve (cylindrical)?

sharp temporal rim
C/D = 0.15-0.65
cupping = 1=5 diopters in depth


what is the C/D and physiological cupping typically for a type 3 nerve (slope/bowel)?

C/D = 0.15-0.65+
cupping = 1-3 diopters in depth


what is the C/D and physiological cupping typically for a type 4 nerve (hooked)?

C/D = 0.2-0.7+
cupping = 1-5 diopters in depth


what is the ISN'T rule?

the inferior border should be the thickest > Superior > Nasal > Temporal (thinnest)


how is the ISN'T rule helpful in glaucoma?

the vertical C/D increases faster than horizontal - doesn't follow the ISN'T rule


when judging the C/D, where do you measure the disc diameter from?

the first point of deflection of the disc vessels from the neural rim bending towards the optic cup - not color change


what are the average C/D for Caucasians, African Americans and Asian/Latinos?

Caucasians = 0.4
African Americans = 0.6
Asian/Latinos = 0.5


what is a normal amount of asymmetry between the two eyes C/D?

30% = 0.1 difference and 4% have a 0.2 difference


what does a normal healthy, young NFL look like?

with red-free filter it should have a shimmering reflection


what 4 things to you look for during retinal vessel evaluation?

A/V ratio, ALR, delfections or crossing defects, and area around the vessels (white, red, dark stuff)


what is a normal A/V ratio and where do you look to compare?

normal = 2/3 or 3/4
estimation should be made after the first bifurcation and before the third


what should you think if the veins are too wide? or arteries are too narrow?

veins too wide = think diabetes
arteries too narrow = HTN


what is ALR?

arteriolar light reflex - ratio of the width of light being reflected off the surface of the artery to the overall width of the artery


what is a normal ALR?

1/3 or 1/4


what happens to the ALR with arteriosclerosis and HTN?

the ALR thickens - as the walls of the artery thicken, less light is allowed to pass through and more is reflected back


what 4 things can happen to the vessel crossings with arteriolar sclerosis and HTN?

compression, deflection of the underlying vein, humping, and tapering (nicking)


what are tortuous vessels?

vessels appear to be crooked or winding (if both vein and artery, usually congenital)


what are the 5 fundus types?

albino, blonde, brunette, dark, and tigroid


what is difference about an albino fundus?

there is no macular pigment (no RPE layer)


what 5 things do you evaluate in the macula?

even pigmentation, foveal light reflex, hemorrhages, drusen, and pigmented lesions


what is the foveal light reflex (FLR)?

a reflex actually located in the vitreous as a result of the shape of the retina and the "depression" of the fovea


why is the FLR important to find?

if the patient has reduced acuities (20/25 or worse) you need to determine if the macula is the cause of reduction