The feasibility of gamma (gamma)-interferon injection for the treatment of ocular fibrotic conditions was studied in rabbits using recombinant rabbit gamma-interferon and the cell-injection model of tractional detachment. A toxicity study revealed that intravitreal injection of greater than 10(4) units gamma-interferon consistently produced panuveitis. For tractional detachment, 250,000 rabbit dermal fibroblasts were injected intravitreally into 20 eyes; 1 day later, 5 of these eyes received intravitreal injections of 10(4) units gamma-interferon, another 5 were given 10(6) units, and the remaining 10 received balanced salt solution. Slit-lamp examination and fundus photography were performed at regular intervals for 21 days and were graded by a masked observer. The eyes were then enucleated and processed for histology. Doses of 10(4) units gamma-interferon significantly reduced the severity of detachments, but injections of 10(6) units induced panuveitis.