Lutein and Zeaxanthin Supplementation and Association With Visual Function in Age-Related Macular Degeneration

PURPOSE. To evaluate the effects of lutein and zeaxanthin on visual function in randomized controlled trials (RCTs) of AMD patients. METHODS. Relevant studies were identified by searches on PubMed, EMBASE, Web of Science, and Cochrane Library database up to April 2014. Three investigators independently determined the eligibility of RCTs, which compared lutein and zeaxanthin intervention with placebo. The adjusted weighted mean differences (WMDs) from each study were extracted to calculate a pooled estimate with its corresponding 95% confidence interval (CI). The main outcome measurements included visual acuity (VA), contrast sensitivity (CS), glare recovery time (GRT), and subjective perception of visual quality. RESULTS. Eight RCTs involving 1176 AMD patients were included in the meta-analysis. Xanthophyll carotenoids supplementation was associated with significant decrease in logMAR levels compared with the placebo group (WMD, -0.04; 95% CI, -0.06 to -0.03), and during intervention, each 1-mg/day increase in these carotenoids supplementation was related to a 0.003 reduction in logMAR level of VA. Remarkable benefit was also observed at all four spatial frequencies of CS (WMD ranging from 0.08-0.18; all P < 0.05) in contrast to placebo. Furthermore, association was observed between the postintervention increase in macular pigment optical density and improvements in VA (r = -0.58; P = 0.02), and in CS at 12 cycles/degree as well (r = 0.94; P < 0.001). CONCLUSIONS. Lutein and zeaxanthin supplementation is a safe strategy for improving visual performance of AMD patients, which mainly showed in a dose-response relationship.