There is evidence suggesting that the ophthalmia which results from a deficiency of vitamine A is secondary to some change outside the eyes, and that this change may lie in the paraocular glands. In rats these glands consist of the lacrimal, with its watery secretion, the Harderian, with a probable fatty product, and the Meibomian glands. A histological study of these structures shows questionable changes in the lacrimal and Meibomian glands, and marked changes in the Harderian gland.
The changes in the Harderian gland are both degenerative and inflammatory. The degenerative changes consist of swelling, vacuolation, and occasionally complete epithelial disintegration. The inflammatory lesions may be either acute or chronic. The acute reactions are sometimes diffuse, but are more often focal. Definite suppuration occasionally results. The acute process generally passes over into a chronic inflammation with mononuclear cell infiltration, fibrosis, and atrophy. The changes demonstrated indicate a serious disturbance in the secretion of the Harderian gland, such as may conceivably render the conjunctiva susceptible to infection.
Theses studies suggest the importance of investigating the paraocular glands in other types of conjunctival infection. It is possible that they may have a definite relation to the origin and course of such infections.