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Magnifying
glass
III. GUIDELINES FOR ASSESSMENT AND TREATMENT
When confronted by ocular disorders in the wilderness, attempt to measure the visual
acuity. Reading the print in a book or any other printed material will provide at least a
rough measure of visual acuity.
Acute Vision Loss in the Non-inflamed Eye
Disorders that may cause acute visual loss in a non-inflamed eye include retinal
detachment, central retinal artery occlusion, anterior ischemic optic neuropathy, optic
neuritis, central retinal vein occlusion, arteritic anterior ischemic optic neuropathy,
vitreous hemorrhage, and significant high-altitude retinal hemorrhage. These disorders
are difficult to diagnose and treat in the wilderness and, in most cases, all that can be
done is to arrange for an urgent evacuation.
Giant Cell Arteritis: A key question that must be asked is "Does he or she have Giant Cell
Arteritis (GCA)?" This is important because visual loss in one eye due to GCA is often
rapidly followed by visual loss in the other eye if untreated. In addition, untreated GCA
has a significant mortality. Diagnostic factors that may help to identify a person with
GCA are age greater than 55, temporal headache, jaw claudication, fever, weight loss,
previous transient episodes of visual loss, and generalized muscle aches and fatigue. If
GCA is suspected, start the individual on prednisone 80 mg a day and evacuate on an
urgent basis.
Central retinal artery occlusion: The other cause of acute visual loss in a non-inflamed
eye that may sometimes be treated successfully in the wilderness is central retinal artery
occlusion. For this reason, treat acute loss of vision in the wilderness with a trial of
supplemental oxygen, if available, at the highest inspired fraction achievable as soon as
possible after the onset of symptoms. If supplemental oxygen is to be of any benefit, a
response is typically seen within just a few minutes.
Orbital or Periorbital Inflammation
This may result from preseptal cellulitis, orbital cellulitis, orbital pseudotumor, insect
envenomation, or dacryocystitis. Preseptal cellulitis is characterized by periocular
erythema and edema, a history of periocular trauma or hordeolum, no proptosis, no
restriction of extraocular motility, no diplopia, and no change in visual acuity. Treatment
for preseptal cellulitis is gatifloxacin or moxifloxacin 400mg once a day with expedited
evacuation if no improvement is seen in 24-48 hours. Dacryocystitis is a specific type of
preseptal cellulitis in which the source of the infection is an obstructed nasolacrimal duct.
The erythema and inflammation are localized to the area overlying the lacrimal sac at the
inferior nasal aspect of the lower eyelid. It is treated in the same manner as described
above except that warm compresses should also be used. The diagnosis of periocular
