Influence of membrane differential filtration on the natural course of age-related macular degeneration: a randomized trial

Membrane differential filtration is able to optimize rheologic parameters by eliminating high molecular weight proteins and lipoproteins from the blood. Following the hypothesis that these changes result in an improvement of the microcirculation, the authors tested the efficacy of membrane differential filtration in improving visual function in patients with age-related macular degeneration (ARMD). Forty patients (40 eyes) were randomized into two groups. The treatment group was treated five times over a period of 21 weeks. In both groups, 9/20 of the eyes showed subfoveolar subretinal neovascularization. The main parameter of the study was visual acuity (VA). Electroretinogram (ERG), electrooculogram, and macular visual evoked potentials were also recorded. Plasma and whole blood viscosity and erythrocyte aggregation were measured. The 20 patients treated repeatedly over a period of 21 weeks showed a mean improvement of 0.63 lines (SD 1.8) of VA on Early Treatment Diabetic Retinopathy Study charts. The control group showed a deterioration of 0.94 lines (SD 1.7) compared to VA at baseline examination. The amplitude of the ERG photopic a-wave and the flicker ERG was significantly increased. The rheologic parameters were lowered in all treated patients. Repetitive treatment with membrane differential filtration is able to improve visual acuity of patients with ARMD and the natural course of this disease. Several questions arise from the results of this study. Further research will show if it is possible to optimize the selection of patients for subgroups with predictive responses through morphologic and functional tests and how to create an optimized and individual treatment strategy determined by the quality, intensity, and frequency of treatment sessions.