This article is more than 5 years old. Information may no longer be current.
Visual range improves with increased levels of macular pigment
Increased macular pigment allows for better sight through atmospheric scattering or blue haze, according to a study recently published in Optometry & Vision Science.
Fletcher and colleagues conducted an empirical test of the visibility hypothesis of macular pigment.
Researchers tested participants who had no history of ocular disease relevant to the study, Snellen acuity better than 20/40 and the ability to perform study tasks.
As detailed in the study, researchers evaluated the full contrast sensitivity function (CSF) in 12 participants with two background conditions – short wave-deficient light and simulated blue haze. Another group of 25 participants has their CSF measured for one frequency in the same conditions along with a broadband xenon condition to mimic sunlight.
Researchers utilized a three-channel optical system to measure contrast sensitivity and a macular densitometer (Macular Metrics) to measure macular pigment optical density.
Results showed that the simulation of blue haze reduced CSF in the group of 12 participants. Additionally, the researchers reported that macular pigment optical density was significantly associated with the energy needed to render a target imperceptible for the xenon and haze backgrounds, but not the short wave-deficient background.
"It was observed that subjects with higher levels of macular pigment required more simulated haze to lose visibility of a short wave–deficient grating target," the authors stated. "Log energy at threshold varied by a factor of 2 between subjects with the highest and lowest levels of macular pigment, implying that a subject with high MPOD would be able to detect a target at a much greater distance (i.e., more atmospheric haze between them and the target) compared with a subject with lower MPOD."
They also noted that for the xenon background, there was nearly a twofold difference in the amount of energy needed to lose sight of a target between participants with the highest and lowest levels of macular pigment.
"The next obvious step is to conduct a similar study using subjects with a wide range of MPOD in an outdoor setting for maximum ecological validity," the authors concluded. "Finding that the same relationship exists outside the carefully controlled laboratory setting would perhaps provide the impetus for conducting measurements of macular pigment (and subsequent supplementation for subjects found to have low levels) in subjects whose visual-motor performance could be enhanced by better vision outdoors."
Disclosure: The authors reported no relevant financial disclosures.