Experimental immunogenic rubeosis iridis.

We have developed a primate model of rubeosis iridis in monkeys systemically sensitized to crystalline beef insulin. After intravitreal insulin injection, the dose-related immunogenic inflammation includes cells, flare, fibrin, and blood in the anterior chamber. With more severe inflammation, posterior synechiae, iris bombé, and cataracts occur. Of particular importance, new blood vessels develop within the stroma and on the anterior surface of the iris. Following injection of small amounts of insulin, the anterior surface vessels may regress over time, and the iris regains its normal appearance and coloration. However, the new stromal vessels persist and are cuffed by inflammatory cells including plasma cells. After injection of large amounts of insulin, more extensive structural alterations develop as noted above in conjunction with persistent iris anterior surface and stromal neovascularization. The relationship of rubeosis iridis to clinical inflammatory syndromes and to previous laboratory studies is discussed. Stromal neovascularization was a consistent finding in this experimental model even when anterior surface vessels regressed. On the basis of these experimental data and a review of publications describing human pathology, we believe that a broadening of the classic definition of rubeosis iridis is waranted to include a recognition of the stromal component of the clinical and pathologic findings.