EFFECT OF INTRAVITREAL TISSUE-PLASMINOGEN ACTIVATOR ON EXPERIMENTAL SUBRETINAL HEMORRHAGE

Purpose: To study the effect of intravitreally injected tissue plasmin ogen activator (tPA) in an experimental model of subretinal hemorrhage . Methods: Autologous blood was transsclerally injected into the subre tinal space in 34 albino rabbits. One day later tPA was injected into the posterior vitreous in 24 eyes and saline was injected into 10 cont rol eyes. Lysis of the subretinal blood was assessed ophthalmoscopical ly and retinal function was evaluated electroretinographically. Result s: In all eyes in which tPA was injected intravitreally 1 day after su bretinal injection of blood, the formed subretinal clot was not visibl e within 24 hours of treatment. Liquefied subretinal blood that formed from clot lysis disappeared within 6 days. Conversely, in all saline- injected control animals, the subretinal clots were unchanged at 24 ho urs and were observed for at least 3 days after injection. As a result of the presence of subretinal blood, scotopic electroretinogram ampli tudes were markedly reduced in the tPA and saline-injected groups. In many eyes, blood migrated from the subretinal space into the vitreous, but it was detected later, was less severe, and cleared more rapidly after tPA injection. Conclusion: Intravitreal injection of tPA 1 day a fter subretinal injection of blood in rabbits facilitated more rapid l ysis of the clotted blood, however, retinal damage was not prevented.