[Preretinal vitreous liquefaction following fundus photocoagulation in young rabbits]

We examined the vitreous change after the retina was destroyed by photocoagulation. Multiple photocoagulation with continuous-wave xenon or diode laser was used to create coagulated spots with 5 disc diameters near the optic disc in 26 eyes of 13 pigmented rabbits aged four weeks. After clinical observation, the eyes were enucleated at 2 weeks and 3, 4, and 14 months after photocoagulation. The vitreous was stained with fluorescein and examined by slitlamp while immersed in water. The vitreous remained unchanged in 2 eyes at 2 weeks after photocoagulation. A liquefied lacuna of the vitreous had formed anterior to the retinal scar in 20 eyes (83%) at 3, 4, and 14 months after photocoagulation. The liquefied lacuna assumed a columnar shape with its bottom corresponding to the retinal scar in 2 eyes at 14 months after photocoagulation. These results show that localized liquefaction in the posterior vitreous can be induced by fundus photocoagulation. It appeared that the presence of a normal retina is one of the prerequisites of integrity of the vitreous in young rabbit eyes.