There is usually no difficulty in distinguishing an attack of acute primary glaucoma from acute iritis. However, if the patient is first seen soon after the hypertensive phase has spontaneously subsided, the condition may be easily mistaken for acute iritis. This occurred in the case to be reported. P. L., a white woman aged 71, was seen in the outpatient department of the Massachusetts Eye and Ear Infirmary, complaining of a foreign-body sensation in the left eye, along with photophobia of two weeks' duration. These complaints were preceded by severe, sudden pain in the left eye, which had gradually abated in the previous week. The right eye had been injured 45 yr. ago and was enucleated 20 yr. later. Examination of the eye revealed the following condition: The right socket showed nothing abnormal. Examination of the left eye was made difficult because of severe photophobia. Vision was 20/70 and was