SEP 24, 2013
Daily supplementation with lutein/zeaxanthin had no statistically significant effect on rates of cataract surgery or vision loss, Age-Related Eye Disease Study 2 (AREDS2) researchers reported in this study. However, they suggest the possibility that supplementation may be beneficial for less well-nourished populations.
AREDS2 is a multicenter, double-masked clinical trial that enrolled 50- to 85-year-olds at risk for progression to advanced AMD. Participants were randomly assigned to daily placebo, lutein/zeaxanthin (10mg/2mg), omega-3 long-chain polyunsaturated fatty acids (1 g) or a combination.
A total of 3,159 AREDS2 participants were phakic in at least one eye and 1,389 of 6,027 study eyes underwent cataract surgery during the study, with median follow-up of 4.7 years.
The five-year probability of progression to cataract surgery in the no lutein/zeaxanthin group was 24 percent. For lutein/zeaxanthin vs. no lutein/zeaxanthin, the hazard ratio for progression to cataract surgery was 0.96 (P = 0.54). For participants in the lowest quintile of dietary intake of lutein/zeaxanthin, the hazard ratio comparing lutein/zeaxanthin vs. no lutein/zeaxanthin for progression to cataract surgery was 0.68 (P = 0.03).
The hazard ratio for three or more lines of vision loss was 1.03 for lutein/zeaxanthin vs. no lutein/zeaxanthin.
The authors note that the reduction in the serum levels of lutein/zeaxanthin in participants who received both carotenoids may be the result of the apparent systemic competitive absorption of carotenoids.
They also note that the mean age of AREDS2 participants at enrollment into the follow-up study was 72 years. At that time, 42 percent already had some cortical opacities and 8 percent had some posterior subcapsular cataract opacities. Given the advanced age of participants, cataracts may have already begun to develop in many who had no apparent opacities at the start of the study. Perhaps the intervention was too late or of insufficient duration to affect the outcomes.