Double perforating ocular injuries were made in 30 rabbits and the effects of radiotherapy (RT) alone or in combination with cyclosporin (CS) on vitreous proliferation investigated. Thirteen rabbits in group 1 received RT alone (600 cGy), and 13 rabbits in group 2 received RT combined with 100 mu g of intravitreal CS. No treatment was given to 4 rabbits in the control group ( group 3). All animals were ophthalmologically examined on the 1st, 3rd, 7th, 14th and 28th days following the injury and the clinical findings scored; they were sacrificed on the 28th day, and histopathological scoring was made. The median histopathological score of the RT group (4.0; range: 0-8) was significantly higher than that of the CS + RT group (1.0; range: 0-5; p = 0.018). We conclude that intravitreal CS may be used as an adjunctive agent to RT to inhibit intraocular proliferation following penetrating ocular injury in rabbits. Copyright (c) 2006 S. Karger AG, Basel.