Basic Eye Exam

Question 1

Refractive power provided by cornea and lens?

Answer 1

cornea = 2/3 of refractive power
lens = 1/3

Question 2

emmetropia

Answer 2

eye is correct length; image focuses on the retina

Question 3

hyperopia

Answer 3

the eye is too short so the image gets focused behind the retina

Question 4

myopia

Answer 4

the eye is too long and the image focuses in front of the retina

Question 5

astigmatism

Answer 5

refracting power of the cornea is different in one meridian v. another so the image is blurred in one spot more than another

Question 6

presbyopia and how to correct for it

Answer 6

lens loses its ability to accommodate; happens normally w/ age (mid 40s); the lens become more convex; distance vision unchanged but near vision diminished
Correction: glasses, contact lenses
refractive surgery (LASIK) does NOT correct presbyopia

Question 7

Terminology: VA, OD, OS, OU, cc, sc

Answer 7

VA = visual acuity
OD = oculus dexter = R eye
OS = oculus sinister = left eye
OU = oculus uterque = both eyes
cc = w/ correction
sc = w/o correction

Question 8

critical that VA be checked in kids before what age and why?

Answer 8

have to check before age 7 (age 5 even better) b/c the visual cortex becomes locked after that; at that age the best the eye has seen will be the best it can be; after age 7 the brain will not be able to improve its connections

Question 9

color deficiency prevalence

Answer 9

congenital color deficiency - 8% of males (red/green) 0.5% females; X-linked recessive
test w/ Ishihara plates

Question 10

fluorescein staining purpose?

Answer 10

used to detect a corneal epithelial defect; use a Woods lamp or cobalt blue filter

Question 11

upper lid eversion?

Answer 11

flipping the eyelid to look for a foreign body

Question 12

anterior chamber depth assessment?

Answer 12

use when you suspect narrow angle glaucoma prior to dilation

Question 13

tonometry and normal IOP?

Answer 13

method of measuring eye pressure; important especially for glaucoma; normal IOP = 8-21mm Hg

Question 14

VA definition; normal ranges; what the numbers mean; near normal, moderate low vision, legal blindness ranges

Answer 14

VA is not vision but the ability to resolve a certain size object at a given distance
“normal” is 20/20 but normal range is from 20/12 to 20/25
the first # is how far you are from the chart and the second # is how far a “normal” person would be standing from the chart and be able to read that line - ex: 20/100 means that what you can read standing 20’ from the chart a normal person could read from 100’ away
20/20 - 20/70 = near normal
20/80 - 20/160 = moderate low vision
20/200 or less cc w/ the better eye or less than 120 degrees of field, severe low vision = legal blindness

Question 15

structures to observe/palpate for external eye exam?

Answer 15

observe lids, surrounding tissues, palpebral fissures

palpate orbital rim or lids and lymph nodes (particularly preauricular and submandibular; could also check submental)

Question 16

APD aka Marcus-Gunn: what is it, how to test for it, implications for area of injury

Answer 16

APD = afferent pupillary defect
swing flashlight test to find it
means that the signal from one eye is making it back to the brain better than the other
means the injury has to be anterior to the optic chiasm
exam would show normal consensual response in affected eye but not a normal direct response i.e. the eye won’t constrict when you shine the light in it

Question 17

location of optic disc compared to fovea; best angle to approach pt during ophthalmoscope exam

Answer 17

optic n. is 15 degrees nasal to the central macula; so you want to approach the pt’s eye at a 15 degree temporal angle

Question 18

In what order do you inspect internal eye structures in ophthalmoscopy and why?

Answer 18

order: optic disc, retinal blood vessels, periphery, macula, fovea
the macula and fovea are the most light sensitive so that’s why you exam them last

Question 19

red reflex: what is it, how should it look, what distance should you view it from?

Answer 19

red reflex = reflection of light off the retina
visualize RR 1 ft. from the pt and adjust diopter wheel to make it crisp/clear (if you’re in focus for the RR you will be in focus for the retina)
normal RR should be evenly colored and not interrupted by shadows; should be symmetrical in both eyes

Question 20

appearance of normal optic n. and location; what is the central depression and its relation to glaucoma

Answer 20

normal optic n. = vertically oval and pink; located 15 degrees nasal to fovea; average = 1.5 x 1.7mm but varies widely b/w pts
Central depression = physiological cup; one indicator of glaucoma is and increased cup:disc ration (>0.50)

Question 21

Basic Eye Exam Steps (11 of them!)

Answer 21

1. Measure VA in each eye
2. Perform confrontational visual field for each eye
3. Inspect lids and surrounding tissues (external exam)
4. Inspect conjunctiva and sclera
5. Test EOM
6. Test pupils for direct and consensual responses
7. Inspect cornea and iris
8. Assess the anterior chamber for depth and clarity
9. Assess lens for clarity w/ ophthalmoscope (red reflex)
10. Perform ophthalmoscopy
11. Determine if referral is appropriate