Visual fatigue, caused by many factors, not least staring at computer monitors for long hours, may be eased a daily supplement containing blackcurrant fruit extract (200 mg), lutein (5 mg), and zeaxanthin (1 mg), according to a randomized, double-blind, placebo-controlled cross-over trial.
The findings, published in the journal Applied Ergonomics, adds to the ever growing body of science supporting the eye health benefits of lutein and zeaxanthin.
Lutein, a nutrient found in various foods including green leafy vegetables and egg yolk, has a ten-year history in the dietary supplement market as a nutrient to reduce the risk of age related macular degeneration (AMD). It is often used in combination with zeaxanthin.
The global lutein market is set to hit $124.5 million (€93 million) in 2013, according to a 2007 report from Frost & Sullivan.
According to the report, manufacturers need to address this growing maturity in dietary supplements by identifying new and potentially lucrative application segments that offer opportunities for the continued growth of the lutein market.
Looking at visual fatigue
Researchers from Kwansei Gakuin University in Japan and Singapore's Cerebos Pacific Limited, which supplied the supplement used in the study, recruited 22 people to participate, 13 of whom actually completed the study.
The subjects were randomly assigned to receive either the lutein supplement, or placebo, for two weeks, followed by two weeks of washout, and a further two weeks with the opposite intervention.
After completing a two hour visual proof reading task, the researchers measured signs of visual fatigue, including so-called eye fixation related potentials (EFRP).
“EFRP is thought to reflect the total functioning of the visual system, consisting of the retina, the muscle of the pupil, the muscles involved in eye movements, and central nervous system functioning,” explained the researchers.
“In the present study, [a supplement containing lutein, zeaxanthin, and blackcurrant extract] may have had beneficial effects on visual functioning that served to counteract or prevent fatigue induced by the proof reading task,” they added.
“Overall, our results suggest that a combination of lutein, zeaxanthin and blackcurrant extract can aid recovery from visual fatigue,” they concluded.
Source: Applied Ergonomics
Volume 40, Issue 6, Pages 1047-1054
“The effect of lutein supplementation on visual fatigue: A psychophysiological analysis”
Authors: A. Yagi, K. Fujimoto, K. Michihiro, B. Goh, D. Tsi, H. Nagai