The study of etiology of phlyctenular disease of the eye is instructive to the internist and to the oculist. The opinion is almost universal that the repeated formation of phlyctenules is a manifestation of tuberculosis. The character of the corneal involvement in systemic disease or focal infection varies according to individual idiosyncrasy and, while we can readily accept in some patients the tubercular origin, in others we cannot, or, if the dyscrasia should be tubercular the corneal disease may take other forms, such as sclerosing keratitis, numerous fine points of infiltration, keratitis secondary to iritis, or lupus.
The published evidence for the tubercular origin of phlyctenular disease is strong. Goldbeck1 studied thirty-nine cases thoroughly and systematically. Some of his conclusions are worthy of thoughtful consideration.Predisposing Causes.—The nodular cellular lymphoid deposits (phlyctenules) are local eye manifestations of a constitutional dyscrasia strongly suggestive of tuberculosis—if not tuberculosis—then