Atrophy of the iris is seen in a variety of conditions, and Duane, in his translation of Fuchs'1"Text Book of Ophthalmology," states that it may supervene as the result of (1) long-continued or recurring inflammation, (2) increase of tension involving the blood vessels at the root of the iris, (3) traction on the iris or iridodialysis, (4) too thorough absorption of swelling lenticular material or (5) advanced age or without recognizable cause. Essential atrophy of the iris—the atrophy without recognizable cause —is not often reported, and knowledge of it is therefore imperfect. The atrophy is progressive, so that congenital anomalies, such as aniridia or colobomas, can be easily ruled out, and little is known concerning its primary cause. The following case has been seen at intervals for the past six years, and on three occasions sketches were made which show the progress of the atrophy which