Purpose: To investigate the ultrastructure of the vitreoretinal interface following an intravitreal injection of plasmin.
Methods: Plasmin (2 U/0.1 ml) was injected into the vitreous cavity of five postmortem human eyes. The five fellow eyes received phosphate-buffered saline and served as controls. After incubation at 37 degrees C for 30 minutes, the globes were placed in fixative and hemisected. Specimens for scanning and transmission electron microscopy were obtained using a corneal trephine.
Results: All plasmin-treated eyes showed complete vitreoretinal separation with sparse collagen fibrils covering the inner limiting membrane. All control eyes showed an attached cortical vitreous. At the vitreous base, there was no cleaving effect. The retinal morphology of plasmin-treated eyes was unchanged.
Conclusions: Plasmin induces a cleavage between the vitreous cortex and the inner limiting membrane without morphologic alteration of the retina.