Abstract
Purpose:
Diabetic retinopathy (DR), which occurs after various duration of diabetes (DM), may result in significant visual impairment or blindness. Therefore, early DR prophylaxis and treatment is substantial. The complex etiopathogenesis of DR results from biochemical abnormalities in the retinal nervous and glial cells, and blood flow dysfunctions in the retinal microcirculation. One of early symptoms of functional retinal disorder in DM is diminished contrast sensitivity (CS). Alpha-lipoic acid and vitamin B1 have proven therapeutic effect in the prophylaxis and treatment of diabetic peripheral neuropathy. The aim of our study was to investigate the effect of oral administration of alpha-lipoic acid, vitamin B1, vitamin B2 and rutoside on CS in patients with type 1 (DM1) and type 2 (DM2) diabetes, without DR or with non-proliferative DR.
Methods:
The study involved 12 patients with DM1 (22 eyes), 48 patients with DM2 (83 eyes) and 20 healthy people (38 eyes). Patients from each studied group were randomly assigned to receive once daily 1 capsule of Retixoft, a dietary supplement containing: 300 mg of alpha-lipoic acid, 1.1 mg of vitamin B1, 1.4 mg of vitamin B2 and 25 mg of rutoside) for 3 months. CS was evaluated by the Functional Acuity Contrast Test (FACT, Stereo Optical) in different spatial frequencies (1.5, 3, 6, 12, and 18 cycles per degree [cpd]) with a contrast-level change step corresponding to 0.15 log contrast sensitivity (logCS).
Results:
Among the group receiving Retixoft, CS remained unchanged in all spatial frequencies in patients with DM1 and improved at frequencies 12, 18 cpd in patients with DM2. Among the patients without Retixoft supplementation, a significant CS deterioration was observed at spatial frequencies 1,5, 3, 6, 12 cpd in DM1 patients and significantly decreased at spatial frequencies 1,5, 3, 6 cpd in DM2 patients. In the control group CS remained stable among the ones without Retixoft supplementation, while a significant CS improvement after Retixoft supplementation at special frequency 3 cpd was observed.
Conclusions:
Alpha-lipoic acid, vitamins B1 and B2, and rutoside sustain or improve CS in patients with DM1 and DM2, and can be considered as an early prophylaxis and treatment of DR.
Keywords: 498 diabetes •
499 diabetic retinopathy •
478 contrast sensitivity