EYE DISORDERS - Medicine for Mountaineering and Other Wilderness Activities - page 194

Bacterial conjunctivitis often begins with an abrupt onset and usually spreads from the
initially affected eye to the other eye within forty-eight hours. It is characterized by red-
ness, tearing, and irritation throughout its course and often produces a purulent discharge.
Swollen lymph nodes are usually not present, although bacterial conjunctivitis can follow
an episode of viral conjunctivitis.
Allergic conjunctivitis is most often characterized by redness, itching, tearing, and
sometimes nasal congestion. It is almost always in both eyes and will subside once the of-
fending agent is removed. A variety of substances can cause allergic conjunctivitis, includ-
ing pollen, animal dander,and dust. It occurs more often in people with a history ofallergy
problems.
The goal of treating conjunctivitis is to relieve the symptoms and to prevent or treat an
infection if present. In general, treatment for bacterial and viral conjunctivitis should be
the same—application of artificial tears as needed to provide comfort and application of
an antibiotic four times a day. The antibiotic both treats bacterial infections and prevents a
secondary bacterial infection if the infection is viral in origin. If the conjunctivitis appears
to be clearly allergic in nature, artificial tears help dilute the offending allergen and relieve
some of the itching. Antihistamine drops or a combination antihistamine/vasoconstrictor
canalsobeusedinallergicconjunctivitistoeffectivelyrelievesymptoms.Theseshouldnot
be used for more than two to three days as they can cause a reactive redness and itching.
Subconjunctival Hemorrhage
A subconjunctival hemorrhage is easily differentiated from other causes of red eye. It is
a benign condition, though it rarely may be associated with other more serious disorders,
such as bleeding disorders or hypertension. The appearance is distinct from conjunctivit-
is in that the redness is uniform and possesses distinct borders, completely obscuring the
sclera that it covers ( Fig. 15-1 ) . It causes no pain, visual changes, or discharge and is a
selflimiting condition that should resolve completely within one to two weeks depending
on its size. The person should be reassured that continuing outdoor activities is safe.
Figure 15-1. Subconjunctival hemorrhage
Iritis, Scleritis, and Acute Angle-Closure Glaucoma