Alterations in the vitreo-retinal barrier can modify the exchange of water taking place between the retina and the vitreous body and cause retinal edema to develop. To verify this fact, albino rabbits were subjected to vitrectomies perfusing various intraocular irrigating solutions for various durations. The following conclusions were drawn from these experiments: Ringer's Lactate and physiological saline solutions are more edematogenous than BSS plus; the induced edema is more severe, the longer the perfusion.We have also confirmed that this edema is inhibited by topically administered indomethacin, which proves that in the rupture of blood-retinal barriers during the vitrectomy, prostaglandins play an important role.