An experimental model of preretinal neovascularization in the rabbit

Although progressive retinal neovascularization is a potentially blinding complication of several diseases, there are no good animal models. The authors developed a consistent model of preretinal neovascularization in the rabbit by partially digesting the posterior vitreous with repeated injection and aspiration of 1 IU of hyaluronidase before injection of 250,000 homologous dermal fibroblasts. The evolution of the new preretinal vessels was monitored by indirect ophthalmoscopy, fundus photography, and fluorescein angiography. A grading system was devised using fundus photographs and fluorescein angiograms to describe the progression of new vessel growth and the extent of fluorescein leakage. Ninety-five percent of the eyes had vascular enlargement and hyperemia but no fluorescein leakage by day 1. Fifteen percent of the eyes had clinically evident new preretinal vessels, and 32% had severe fluorescein leakage by day 7. Ninety-five percent of the eyes had definite neovascularization by day 14. Severe fluorescein leakage peaked at day 14 (55% of the eyes) and decreased thereafter. Involution or atrophy of the vessels occurred in all eyes by day 42. This model will be useful for studying the pathogenesis of preretinal neovascularization and evaluating potential treatments for its prevention.