Abstract
Abstract: :
Purpose: To study possible short-term effects of lutein supplementation on vision measures in retinitis pigmentosa patients, in a 48-week placebo controlled, randomized crossover study, following patients' positive vision changes in a non-randomized pilot study (Zorge, ARVO 1999). Methods: Forty-four patients with typical RP and 11 with related retinal degenerations were enrolled and stratified (vitamin A use and iris color) into two groups: Placebo (24 weeks placebo, 12 wks 10 mg/day, 12 wks 30 mg/d) and Washout (12 wks 10 mg/d, 12 wks 30 mg/d, 24 wks placebo). Subjects returned for clinical exams and visual function tests once per 6 weeks. Vision measures included ETDRS visual acuity at 100% and 4% illumination (each eye), and Pelli-Robson contrast sensitivity at 100%, 4% and glare (BAT, high setting) illumination (better eye only). The seven measures were analyzed separately for significant effects of lutein supplementation, and a joint visual function measure was constructed for each subject, by weighting each test result with the inverse of its visit-to-visit variability. Humphrey 10-2, macular pigment density, and dark adaptation measures will be reported elsewhere. Results: Eighteen Washout and 24 Placebo subjects completed the study. For a few visual function measures (notably low luminance VA and CS), differences between Washout and Placebo groups showed a trend towards beneficial effect of lutein supplementation approaching statistical significance, but for other measures, including the compound score, no beneficial effect of lutein supplementation was found. There were no significant differences in findings according to vitamin A use or iris color. Conclusions: Previously reported beneficial effects of lutein supplementation in RP are not confirmed by these clinical vision measures in a randomized, placebo controlled trial. Interestingly, however, subjects' personal reports concerning changes in vision did correlate highly with changes in supplement, and of 13 subjects leaving the study in the first 24 weeks, 11 were on placebo (p<.07). Therefore, it is possible that subtle benefits of lutein are missed by measures reported here. We continue to analyze results of remaining clinical vision measures, and test data collected on home PCs by the same subjects.
Keywords: clinical (human) or epidemiologic studies: tre • clinical research methodology • retinitis