Improvement of macular function by membrane differential filtration in diabetic retinopathy

Alterations of blood rheology are assumed to substantially contribute to the pathogenesis of diabetic retinopathy. Membrane differential filtration (MDF) is an extracorporeal treatment which is able to optimize rheological parameters by eliminating high molecular weight proteins and lipoproteins from the blood. The present study was designed to investigate the effects of repetitive MDF on visual function in diabetic retinopathy.

11 patients (11 eyes) with nonproliferative or inactive proliferative diabetic retinopathy underwent three treatment cycles during a mean period of 18 weeks. The best corrected visual acuity served as the main parameter of the study. The measurement of visual acuity, visual field, biochemical and rheological parameters was carried out 24 hours pre and post each treatment cycle and at follow up. The mean follow up time was 9 weeks during the post treatment period.

Compared to baseline examination the visual acuity improved stepwise by a mean value of 1.4 lines (p = 0.02) after the last treatment and remained stable at follow up (1.3 lines, p < 0.001). The mean defect of the visual field was reduced by 2.8 dB (p = 0.13) after the treatment period and by 2.5 dB (p = 0.016) at follow up, respectively.

Repetitive treatment with membrane differential filtration is able to improve visual function in patients with diabetic retinopathy. The present study suggests that repetitive membrane differential filtration treatment could be a useful adjunct along with laser treatment to influence the clinical course of diabetic maculopathy.