Background and objectives: The purpose of this study was to determine whether supplementation with lutein improved visual function in patients with nonproliferative diabetic retinopathy (NPDR).
Methods and study design: In this randomized, double-blind, placebo-controlled trial, 31 patients with NPDR were assigned randomly to 10 mg/d of lutein or identical placebo for 36 weeks. Visual performance indices, including visual acuity (VA), contrast sensitivity (CS) and glare sensitivity (GS) at four different spatial frequencies, were measured at baseline, week 18 and 36.
Results: At 36 weeks, a slight improvement in VA was found in the lutein group. A significant association was observed between the changes in VA and the corresponding baseline values in treatment group (r=-0.53; p=0.04). At 36 weeks, the lutein treatment group increased CS at four spatial frequencies, and the improvement achieved statistical significance at 3 cycles/degree (p=0.02). The changes in CS at 3 cycles/degree for the lutein group was marginally significantly greater than those for the placebo group (p=0.09). There was also a slight increase in GS in the lutein group up to week 36, however, no significant changes were found over time in any cycles/degree.
Conclusions: In patients with NPDR, supplementation with lutein resulted in potential improvements in CS at low spatial frequency. Further studies are required to determine the possibility that such intervention could be used as an adjunct therapy to prevent vision loss in diabetic patients.