Thelazia californiensis conjunctival infestation.

There are few reports of Thelazia californiensis infestation in humans in the literature. The authors report the clinical and histopathologic features of two patients who presented with symptoms of a mild unilateral chronic conjunctivitis from infestation by this parasite. In each case, the symptoms resolved immediately after removal of the worms. These are the first two patients from the Rocky Mountain area to be described with an infection from this particular worm. T. californiensis should be included in the differential diagnosis of patients with chronic conjunctivitis following hiking or camping in the mountains or back-country.