EYE DISORDERS - Medicine for Mountaineering and Other Wilderness Activities - page 193

near objects that are brought to a point in front of the eye where accommodation is totally
relaxed.
Considering the number of factors influencing function of the eye, it is a remarkable in-
strument, able to adapt to a variety of environments. However, exposure to the elements
in wilderness environments offers unique challenges and can cause problems ranging from
bothersome to severe.
RED EYES
Eye problems result in a number of different signs and symptoms. Often pain, visual
changes, itching, irritation, and other symptoms signify a problem. One of the most com-
mon signs of a problem is a red or inflamed eye. Individuals should have a framework for
evaluating a red eye in outdoor situations.
First is understanding the common causes of red eyes in such settings. Second is identi-
fying the different etiologies. Last is treating the eye based on the etiology, and knowing
when to evacuate to professional medical care.
Conjunctivitis
One of the most common causes of a red eye is conjunctivitis. The conjunctiva is a thin
clear membrane that lines the inner part of our eyelids and the sclera, the white part of the
eye. The area that coats the inner part of our eyelids is the palpebral conjunctiva, and the
area that coats the sclera is the bulbar conjunctiva. Conjunctivitis means “inflammation of
the conjunctiva.” It has four important etiologies:
Allergies
Viral infections
Bacterial infections
Trauma
Conjunctivitis is usually characterized by dilatation of blood vessels causing redness,
swelling, and a discharge or tearing. The palpebral conjunctiva is always involved with
conjunctivitis, which helps differentiate that disorder from other causes of red eye. Symp-
tomsofconjunctivitisdifferslightlydependingontheetiology,butitisnotalwayspossible
or necessary to identify the etiology. Viral infection is the most common cause of con-
junctivitis. Usually the bulbar conjunctiva is red, and a watery discharge may be present.
Viral conjunctivitis often occurs at the same time or shortly after an upper respiratory in-
fection. The presence of swollen lymph nodes in front of the ear is strongly suggestive but
rarelypresentwithviralconjunctivitis. Itisusuallyaself-limiting conditionbutsometimes
can move from one eye to the other after a few days. The condition is very contagious dur-
ingthisperiod,andtheaffectedindividualshouldtrytominimizecontactwithothersinthe
party.