A carotene, mostly beta-carotene, and saw that individuals who had low dietary intakes did not appear to have higher risks of cataract relative to those individuals who had high intakes of carotene. Susan Vitale and coworkers used data from the Baltimore Longitudinal Study of Aging to relate plasma antioxidants to risk of cataract. In another cross-sectional study, the investigators from the Nutritional Factors in Eye Disease Study of Beaver Dam, Wisconsin, looked at individual carotenoids both within the plasma and in the diet. Those data are based solely on levels in serum collected at the time of the exam. When the Beaver Dam Eye Disease Study investigators examined their subjects for cataracts and took their plasma samples, they also gave them a food frequency questionnaire and asked them to fill it out according to what they had consumed on average 10 years earlier.
High lycopene intake again appears to slightly increase risk in women.
There is again a suggestion that lutein reduces risk. The differences in methodology may explain some of the differences between the effects of the serum and dietary intakes in this study. Two prospective studies have looked at the relationship between carotenoids and cataract. Both used surgical cataract extraction as an endpoint, rather than cataract per se. A study from Finland documented cataract extractions in a group of individuals over a 15-year period.