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insect envenomation is made when the periocular erythema and edema are associated
with an insect envenomation by history or by identification of a papular or vesicular
lesion at the site of envenomation. Treatment is with cool compresses and antihistamines.
Also give gatifloxacin or moxifloxacin 400mg once a day if secondary infection is
suspected on the basis of increasing pain, redness, or swelling. Orbital cellulitis will also
have periocular erythema and edema, but these signs will typically be accompanied by a
history of sinusitis or upper respiratory tract infection, proptosis, diplopia, restricted
extraocular motility, decreased visual acuity, and/or fever. Orbital cellulitis is a life-
threatening disorder and is treated with gatifloxacin or moxifloxacin 400mg once a day,
decongestants, and urgent evacuation.
Acute red eye
The differential diagnosis of the acute red eye includes both obvious and occult open
globe injury, corneal abrasion or ulcer, subconjunctival hemorrhage, traumatic and non-
traumatic iritis, hyphema, herpes simplex virus keratitis, corneal erosion, acute angle-
closure glaucoma, scleritis, conjunctivitis, blepharitis, ultraviolet keratitis, episcleritis,
conjunctival foreign body, dry eye and contact lens overwear syndrome. There a few
simple diagnostic steps that can be undertaken that will help to differentiate between the
entities listed.
Diagnostic Approach to the Acute Red Eye in the Wilderness
Trauma No
Trauma
- Obvious Open Globe
- Fluorescein test
- Fluorescein test
- Response to topical anesthesia
-
Pupillary
status
The first step is to inquire whether there has been recent trauma to the eye. If
there has, the eye should be checked with a light source immediately to see if there is an
obvious open globe. This type of injury is most often encountered in the presence of
lacerating or impaling trauma, such as from a knife wound, a fishhook, or a tree branch or
thorn impaling the globe. Should an obvious open globe be noted, immediately place a
rigid shield (NOT a pressure patch) over the eye to protect it from further trauma. Start
the victim immediately on gatifloxacin or moxifloxacin 400mg once daily and arrange for
an urgent evacuation. Posttraumatic infection of the eye (called endophthalmitis) is a
dreaded complication of an open globe and often results in permanent loss of vision.
If there is a history of eye trauma but no obvious open globe, perform a
fluorescein stain with a fluorescein strip and a drop of topical anesthesia. If an epithelial
defect is seen with the cobalt blue light, the victim has either a corneal abrasion or a
corneal ulcer. Several factors will help to differentiate the two. A corneal ulcer will often
be seen as a white or gray spot on the cornea with a tangential penlight examination. No
opacities or infiltrates are seen with a corneal abrasion. In addition, a corneal ulcer
typically takes a day or two to develop after an episode of trauma and may be
