A new paper published in Exercise and Sport Sciences Reviews by researchers at the University of Georgia proposes that supplementing the diet with colorful fruits and vegetables rich in lutein and zeaxanthin could improve eye health and visual function.
 
These two plant compounds, which are carotenoids, build up within the macula of the eye, and previous studies done by UGA researchers Billy R. Hammond and Lisa Renzi-Hammond found that eating colorful vegetables is linked to improvements in eye and brain health.
 
“A lot of the research into macular lutein and zeaxanthin has focused on health benefits, but from a functional perspective, higher concentrations of these plant pigments improve many aspects of visual and cognitive ability,” said Jack Harth, lead author and doctoral candidate in UGA’s College of Public Health.
 
The authors propose that the ability of macular pigments to filter out damaging blue light from entering the eye can also improve visual range, or how well a person can see a target clearly over distance, which is highly relevant for practically all athletes.
 
“From a center fielder’s perspective, if that ball’s coming up in the air, it will be seen against a background of bright blue sky, or against a gray background if it’s a cloudy day. Either way, the target is obscured by atmospheric interference coming into that path of the light,” said Harth.
 
Previous work had been done testing the visual range ability of pilots in the 1980s, and Hammond and Renzi-Hammond have done more recent studies on how macular pigment density, or how much yellow pigment is built up in the retina, is linked to a number of measures of eye health and functional vision tests.
 
“In a long series of studies, we have shown that increasing amounts of lutein and zeaxanthin in the retina and brain decrease glare disability and discomfort and improve chromatic contrast and visual-motor reaction time, and supplementing these compounds facilitates executive functions like problem-solving and memory. All of these tasks are particularly important for athletes,” said corresponding author Billy R. Hammond, a professor of psychology in the Behavior and Brain Sciences Program at UGA’s Franklin College of Arts and Sciences.
 
Across the range of studies on the topic, there is a significant relationship between macular pigment density and measures which suggest greater visual distance.
 
“We’re at a point where we can say we’ve seen visual range differences in pilots that match the differences found in modeling, and now, we’ve also seen it in laboratory tests, and a future goal would be to actually bring people outside and to measure their ability to see contrast over distance through real blue haze and in outdoor environments,” said Harth.