3. Eye Assessment
6 voluntary muscles rotate & coordinate eye movement
Coordination ensures the retina receives an image at the same time
Muscle around the eye innervated by cranial nerves
◦ II—nerve of sight, connecting optic disc 2 brain
◦ III—oculomotor
◦ IV—trochlear
◦ V—parts stimulates blink reflexes
◦ VI—abducens
◦ VII—innervates lacrimal glands & muscles controlling lid closure
5. Eye Assessment
Refraction: Involves bending light rays from outside n2 eye
Emmetropia—perfect refraction w lens @ rest;, light rays from distant source (20ft.)
Errors of Refraction:
◦ Hyperopia—farsighted not enough light refracted, images fall behind retina, near vision is poor
◦ Myopia—nearsighted eye over bends light & images converge in front of retina, distant vision is poor
◦ Astigmatism—unevenly curved surfaces on or in the eye mainly the cornea, uneven surfaces distort vision
Accommodation
◦ Allow eye 2 focus images sharply on the retina, adjusting focus by changing the curve of lens
Convergence
◦ Ability to turn eye inward @ the same time
Pupillary constriction & dilation—control amount of light entering eye
◦ Constriction = miosis
◦ Dilation = mydriasis
6. Eye Assessment
Aging Eye Changes:
Structural
◦ Decrease muscle tone reduces ability 2 keep gaze focused on a single object
◦ Ectropion—eyelid relax & fall away leads 2 dry-eye symptoms
◦ Arcus senilis—opaque, bluish white ring outer edge of cornea = fat deposits, doesn’t affect vision; will
need extra light to read & avoid tripping over objects
Functional
◦ Yellow lens—reducing ability to transmit & focus light
◦ Lens—hardens, shrinks, loses elasticity = reduced accommodation
◦ Near point of vision increases = presbyopia
◦ Far point of vision decreases = distinguishing objects farthes poin
◦ Both changes narrows visual field
7. Eye Assessment Methods
Patient History
◦ Age
◦ Gender
◦ Occupation
◦ Leisure activities
◦ Systemic health problems
◦ Drugs
Nutritional History
◦ Vitamin deficiency (A need 5-10 servings daily)
Family History & Genetic Risk
Current Health Problems
8. Eye Assessment
Physical Assessment
◦ Inspection: tilting, squinting, symmetry, placement in orbits, hair distribution
◦ Sclera & corneal: with penlight
◦ Pupillary: size, reaction to light, shape, reactivity
◦ Vision Testing
◦ Visual acuity = Snellen chart
◦ Hand motion acuity
◦ Near vision = Rosenbaum Pocket Vision Screener
◦ Visual field = peripheral vision “confrontation test”
◦ Extraocular muscle function = corneal light reflex & 6 cardinal position of gaze
◦ Color vision = Ishihara chart
9. Eye Assessment
Diagnostics
◦ CT: @ eyes, bony structures & extraocular
muscles, tumors in orbital space
◦ MRI: examine orbits & optic nerves & evaluate
ocular tumors but not metal injuries
(contraindicated)
◦ Radioisotope scanning: locate tumors & lesions,
Isotope studies differentiate intraocular tumor
from hemorrhage
◦ Ultrasonography: examine orbit & eye,
noninvasive aids diagnosis of trauma, tumors,
proptosis, choroidal or retinal detachment
◦ Slit-lamp exam: narrow beam of light to locate
position of any abnormality
◦ Corneal staining: fluorescein or topical dye in
conjunctival sac 4 corneal trauma
◦ Tonometry: measure IOP
Ophthalmoscopy: viewing of external & interior structures,
not with confused clients
Fluorescein angiography: detailed image of eye circulation,
photographs in rapid succession w/dye, mydriatic instillation
1 hr before test, drink fluids, yellow or green staining will
disappear few hr, wear dark glasses, avoid direct sunlight =
eye pain
Electroretinography: graphing the retina’s response 2 light
stimulation, detecting & evaluating blood vessel changes, a
contact lens electrodes on anesthetized cornea
Perimetry: screen visual fields looking straight ahead detect
when moving light enter peripheral vision
Gonioscopy: when high IOP, determines open or closed
angle glaucoma, is painless, eliminates corneal curve,
visualizes angle where iris meets the cornea
Laser imaging of retina & optic nerve: 3 dimensional view of
back of the eye, used w. ocular HTN, @ risk 4 glaucoma,
assess thickness & contours of optic nerve & retina 4
changes indicating damage
