They spent three minutes each day looking into the light over a period of two weeks.
The lights work on both cones and rods in the eye. Cones are photo receptor cells that detect color and work best in well-lit situations. Rods, which are much more plentiful, are retina cells that specialize in helping us see in dim light, according to the American Academy of Ophthalmology.
Researchers measured the cone function in subjects’ eyes by having them identify colored letters with low contrast. And they measured their eyes’ rod sensitivity by asking them to detect light signals in the dark. There was a 14% improvement in the ability to see colors, or cone color contrast sensitivity, for the entire two dozen participants. Improvement, however, was most significant in study participants over age 40. For those ages, cone color contrast sensitivity rose by 20% over the course of the study. That age bracket also saw significant increases in rod threshold, which corresponds to the ability to see in low light. Study participants under 40 also experienced some improvement, but didn’t see the same jump as older subjects. Younger eyes haven’t declined as much as older eyes.
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