exam 2 - eyes

palpebral fissure

elliptical open space between eyelids

canthus

corner of eye, angle where lids meet

inner: caruncle is small fleshy mass containing sebaceous glands

conjunctiva

transparent protective covering of the eye

palpebral lines the lids, bulbar overlies the eyeball

cornea

clear, transparent cover that protects the iris and pupil

bends incoming light rays so that they will be focused on inner retina

lacrimal apparatus

provides irrigation to the eye

extraocular muscles

six muscles that attach the eyeball to its orbit and direct eye movement

four rectus muscles, two oblique muscles

cranial nerve VI

abducens nerve, innervates lateral recuts muscle

cranial nerve IV

trochlear nerve, innervates superior oblique muscle

cranial nerve III

oculomotor nerve, innervates superior, inferior, and medial rectus and the inferior oblique muscles

parts of internal anatomy are accessible to exam

anterior sclera, retina using opthalmoscope

internal anatomy of eye

a sphere of three concentric coats: outer fibrous sclera, middle vascular choroid, inner nervous retina 

sclera

tough, protective, white covering

iris

functions as a diaphragm, controlling amount of light admitted to retina

normal appears flat, with round regular shape and even coloration

muscle fibers of iris

contract pupil in bright light and to accommodate for near vision 

dilate pupil when light is dim and for far vision 

pupil

round and regular

size determined by balance between parasympathetic and sympathetic

size reacts to amount of ambient light and to accommodation

retnia

visual receptive layer of eye where light waves changes into nerve impulses

structures viewed through opthalmoscope are optic disc, retinal vessels, general background, and macula

optic disc

area where fibers from retina converge to form optic nerve

located toward nasal side of retina

retinal vessels

paired artery and vein extending to each quadrent

macula

located on temporal side of fundus 

slightly darker pigmented region surrounding fovea, area of sharpest and keenest vision 

images formed on retina…

upside down and reversed

visual pathways of brain

left optic tract now has fibers from left half of each retina, and right optic tract contains fibers only from right; thus, right side of brain looks at left side of world

aging effect on sight

pupil size decreases

presbyopia: lens loses elasticity, becoming hard and glass like, which decreases ability to change shape to accommodate for near vision 

age 70: beginning of cataracts 

glaucoma, age related macular degeneration (AMD), diabetic retinopathy

subjective data

vision difficulty: decreased acuity, blurring, blind spots

pain

strabismus, diplopia 

redness, swelling

watering, discharge

use of glasses or contact lenses

last vision test, smoking status

objective data

position pt standing for vision screening; then sitting up with head at your eye level

equipment needed: smelling eye chart, handheld visual screener, opaque card, penlight, applicator stick, ophthalmoscope

snellen chart

lines of letters arranged in decreasing size

20 ft away

leave glasses or contacts on 

20/30: pt can read at 20 ft when a person with normal vision can read at 30 ft

worse than 20/30: refer to specialist 

OD

right eye

OS

left eye

OU

both eyes

jaeger card

tests near vision

hold card 14 inches away, test each eye separately then together

normally pt can read without hesitancy and without moving card closer or farther away

confrontation 

gross measure of peripheral vision; compares the client’s peripheral vision with you own 

pt covers eye, you cover opposite own eye. slowly advance wiggling finger in from periphery. ask pt to say now when they see it, should also be when you see object too 

corneal light reflex

hirschberg test

assess parallel alignment of eye axes by shining a light toward pt eyes

sparkle should be on same spot in corneas in each eye

asymmetry suggests deviation in alignment from eye muslce weakness or paralysis

diagnostic positions test

cardinal positions

checks for weakness of EOMs, nystagmus, or lid lag and function of CNs

follow movement of finger or object clockwise. pause between movements

inspection of cornea and lens

shine light from side across cornea, and check for smoothness and clarity

should be no opacities (cloudiness) in cornea, anterior chamber, or lens behind pupil

test pupillary light reflex

darken room and ask pt to gaze into distance; this dilates. advance light in from side and not response 

measured in millimeters 

PERRLA

pupils equal, round, react to light and accommodation

strabismus

eyes do not align properly

crossed eye

esotropia

inward turning of eye

exotropia

outward turning of eye

exophthalmos

protruding eyes

enophthalmos

sunken eyes

ptosis

drooping upper lid

ectropion

lower lid rolling out

entropion

lower lid rolling in

blepharitis

chronic inflammation of the eyelids

chalazion 

beady nodule protruding on the lid'; inflammation of a meibomian gland

hordeolum (stye)

acute localization staph infection of the hair follicles at lid margin

anisocoria

unequal pupil size

miosis

constricted and fixed pupils

mydriasis

dilated and fixed pupils

conjunctivities

red, beefy-looking vessels at periphery but usually clearer around iris

itching, burning, foreign body sensation, eyelids stuck together on awakening

contagious

vision unaffected and pupils are normal size and react to light 

allergic conjunctivitis 

upper lid, conjunctiva, and cornea are inflamed from seasonal allergies or persistent allergen 

eye itching, redness, watering, and discomfort 

vision unaffected and pupils are normal size and react to light 

pinguecula

thickening of the bulbar conjunctiva from prolonged exposure to sun, wind, and dust

doesn't cross cornea

pterygium

triangular opaque wing of bulbar conjunctiva overgrows toward the center of the cornea

usually invades from nasal side; and may obstruct vision as it covers pupil

age related macular degeneration 

loss of central vision caused by yellow deposits (Drusen) and neovascularity in the macula 

peripheral vision not affected

glaucoma

increase pressure in eye

primary open angle and primary angle closure

causes irreversible visual field loss; initially causing tunnel vision and then progressing to loss of central vision