Study of Intravitreal Microplasmin in Relieving Vitreo-Macular Adhesion in Neovascular Age-related Macular Degeneration

The human vitreous gel undergoes progressive liquefaction with age. Concurrent with the process of vitreous liquefaction, there is a weakening of the adhesion at the vitreoretinal interface between the cortical vitreous gel and the inner limiting lamina. Posterior vitreous detachment (PVD) is a separation of the cortical vitreous get from the inner limiting lamina. PVD is usually a sudden event during which liquefied vitreous from the center of the vitreous body bursts through a hole in the posterior vitreous cortex and then dissects the residual cortex gel away from the inner limiting lamina. If there is residual vitreoretinal traction around the break, this process may induce a tear in the retina that can in turn result in rhegmatogenous retinal detachment, macular hole, or cystoid macular edema. The importance of the vitreous in the progression of diabetic retinopathy may also extend beyond tractional considerations. For example, it is believed that the vitreous serves as scaffolding for new vessel formation and may also contribute to molecular imbalances that lead to retinopathy progression. Therefore, total PVD, by releasing vitreoretinal traction as well as other potential mechanisms, may be beneficial in various vitreoretinal diseases such as neovascular AMD. Vitreomacular adhesion (VMA) in exudative (wet) AMD may be associated with poor prognosis in patients with AMD. This trial is primarily aimed at showing that release of VMA can be induced by microplasmin, a proteolytic enzyme, in patients with wet AMD, and that microplasmin is safe in patients w/ neovascular (wet) AMD. Secondary endpoint will be assessment of improved AMD outcomes.