Blunt trauma of the eyeball, either through the intervening lid or direct, not infrequently produces a rather characteristic tear of the iris. The tear may involve the pupillary portion of the iris or the peripheral portion, or both, but it is my purpose in this paper to speak only of those tears that are confined to the sphincteral portion. This condition is of fairly common occurrence, but as the majority of cases are not reported or are not diagnosed, the frequency of incidence cannot be estimated. Nearly one hundred years ago, Josenhans1 first described such tears, and since then the literature has been replete with cases. Some of the reports deal only with tears of the pupillary margin of the iris ; others with complicating tears of the periphery of the iris (iridodialysis), while in others an associated dislocation of the lens played a rôle.
MECHANISM OF PRODUCTION
Ruptures of