Cellular immunity to lens protein was studied by leukocyte migration inhibition (LMI). It was studied in patients with various ophthalmological disorders including diabetic retinopathy, and/or cataracts, and/or glaucoma, and in patients with a history of surgical intervention for the relief of increased intraocular pressure and/or cataract extraction. The LMI by lens protein was found principally in patients with past or current inflammatory ocular disease, in particular, anterior uveitis. There was no correlation with the above disorders or operations. Surgery itself did not lead to cellular immunity, while inflammation in the anterior chamber of the eye appears to accompany sensitivity to lens.