Novel vitreous modulators for pharmacologic vitreolysis in the treatment of diabetic retinopathy

Vitreous constitutes about 80% of the volume of the human eye. It is an extended extracellular matrix that is composed of collagen, hyaluronan, and other extracellular matrix molecules, but mostly water. In both health as well as disease, especially diabetic retinopathy (DR), special attention should be drawn to the posterior vitreous cortex and its relation to the retinal surface. The important role of vitreous in the pathogenesis of proliferative DR has already been demonstrated by several experimental and clinical studies. Thus, vitreo-retinal separation by pharmacologic vitreolysis and/or removal by surgical means are appropriate approaches to interrupt the pathogenic contribution of vitreous and prevent progression of diabetic retinopathy to more advanced stages. This review describes various aspects of the molecular morphology and structural anatomy of vitreous and the vitreo-retinal interface, as well as the role of vitreous in the pathophysiology of DR. Lastly, this treatise provides a critical analysis of novel vitreous modulators for pharmacologic vitreolysis in the treatment of DR. Microplasmin is currently the most promising approach to treat vitreoretinal traction by pharmacologic vitreolysis.