Experimental cleavage of chorioretinal scars by traction and subretinal fluid.

The resistance to separation by localized traction and exudative retinal detachment of experimental chorioretinal scars produced with argon laser photocoagulation, cryothermy and diathermy was tested in rabbits. In vivo, the area of retinal separation over the scar was similar to that obtained by traction on normal retina. Moreover, the retinal cleavage occurred at the level of the scar regardless of the scar inducing modality, indicating that the scar is the weakest point in the retina-pigment epithelium joint. However, spaced and dense chorioretinal scars produced by argon laser photocoagulation, diathermy and cryothermy usually remained attached after experimental production of exudative retinal detachments with penicillin G intravitreal injections. This study indicates that the resistance to detachment of the normal retina by traction may be as strong as that of the scarred tissue and that the chorioretinal scars' effect is related to lesser fluid penetration into the treated area.