Abstract
The significance of the presence of 1st instar larvae of the reindeer nostril fly (Cephenomyia trompe L) in the conjunctival sac of reindeer was investigated. The influences of natural ultraviolet radiation upon the development of inflammatory reactions of the eyes was also studied. It is stated that both 1st instar larvae of the Cephenomyia fly, when deposited on the eye, and natural ultraviolet radiation may act as predisposing or enhancing factors in the etiology of keratitis in reindeer. In certain cases keratitis may develop when both parameters are present.