3-23
Visual Fields: Defects seen in optic neuropathies, retinal detachment, GCA, others.
Color Vision: Red image less vivid in optic neuritis
Snellen Chart (if available): Loss of visual acuity may be seen in any of the conditions. Provides baseline
to work from. Decreased vision indicates abnormality in anterior segment (cornea, crystalline lens or iris).
If a Snellen chart is not available, reading the print in a book or other printed material will provide a rough
measure of visual acuity.
Using Advanced Tools:
Ophthalmoscope: Look for intraocular foreign body. If intraocular foreign body found, evacuate immediately
Fundus exam: “Cherry red” spot for CRAO; “blood and thunder” for CRVO
Fluorescein Strip and UV light: Observe for stained tissue indicating corneal abrasion. UV Light intensifies
staining from strips.
Assessment:
Differential Diagnosis
Central retinal artery occlusion (CRAO) - painless, sudden and profound loss of complete vision in one
eye; loss can range from a subtle decrease (uncommon) to a complete loss of all vision; affected eye will
sometimes demonstrate a “cherry red spot” (red spot in the center of a white, swollen retina); typical patient
is sixty or older; profound loss of vision demands any and all measures be taken in attempt to restore any
potential sight. Risk factors include smoking, diabetes, birth control pills and cardiac disease.
Giant cell arteritis (GCA; AKA arteritic anterior ischemic optic neuropathy or temporal arteritis)- gradual
onset of decreased vision with associated temporal headaches, weight loss, jaw pain while chewing, fever,
and/or joint pain; should be ruled out in any patient over 55 years of age with any combination of the above
symptoms; treat quickly, since significant mortality and potential for loss of vision in other eye also.
Retinal detachment (RD) - painless, gradual loss of vision like a “shade,” “veil” or “curtain” being pulled
over the eyes.
Anterior ischemic optic neuropathy (AION) - sudden decrease in vision affecting the lower half of the visual
field in patients up to age 55 years (above 55 years of age giant cell arteritis is more common).
Optic neuritis - central decrease in vision and a color vision deficit, peripheral neurologic signs.
Central retinal vein occlusion (CRVO) - sudden, less profound loss of vision than in CRAO; “blood and thunder”
fundus picture (i.e., massive numbers of retinal hemorrhages)
Vitreous hemorrhage - “shower” of floaters accompanied by significant loss of vision; floaters represent
blood cells casting shadows on the retina after a blood vessel ruptures; occurs in older diabetics, but can occur
after significant trauma, Valsalva and high altitudes.
Plan:
Treatment
Primary:
- Rule out CRAO with a trial of supplemental oxygen at the highest inspired fraction achievable as soon
as possible after onset of vision loss. If supplemental oxygen is to be of any benefit a response is
typically seen in a few minutes. - Start ocular massage immediately in an effort to dislodge any potential embolus (CRAO, CRVO).
Continue for several minutes and abandon if no improvement in symptoms is noted. - Acetazolamide 500mg po initially, then 250 mg po q 6 hours thereafter to lower intraocular pressure
(CRAO, CRVO, Vitreous Hemorrhage, others). - If GCA is suspected, give prednisone 80 mg a day (divided dose) and expedite evacuation.
Primitive: Hyperventilate to decrease the amount of retained carbon dioxide and increase available
oxygen to tissues.
Patient Education
General: Patient has severe visual dysfunction and needs immediate care to have the best chance for
vision recovery.
No Improvement/Deterioration: Return ASAP for evaluation.