Enzymatic vitreous disruption

Abstract

Enzymatic vitreous disruption refers to cleaving the vitreoretinal junction by enzymatic means, thereby inducing posterior vitreous detachment (PVD) and liquefaction of the vitreous gel. Several enzymes have been proposed in this respect, including chondroitinase, hyaluronidase, dispase, and plasmin. In an experimental setting, chondroitinase induced PVD and was helpful in removing epiretinal membranes but no further data have been reported yet. Hyaluronidase liquefies the vitreous as demonstrated in a phase III trial in diabetic patients with vitreous haemorrhage. Dispase induces PVD but also causes inner retinal damage and is now used as an animal model of proliferative vitreoretinopathy. Plasmin has the capability of both PVD induction and liquefaction. However, plasmin is highly unstable and not available for clinical use. Microplasmin (ThromboGenics Ltd, Dublin, Ireland) is a truncated form of human plasmin sharing the same catalytic activity like plasmin. Recombinant microplasmin is under clinical investigation in patients with vitreomacular traction. This review article reports on the current knowledge of enzymatic vitreous disruption and discusses details of the enzyme candidates in basic and clinical research terms.