The relationship between the macular carotenoids and simulated visual range

It has been hypothesized (the visibility hypothesis) that macular pigment (MP) may improve vision through the atmosphere by absorbing "blue haze" (short-wave dominant light that veils distant targets). Past studies have shown other visual effects driven by screening short-wave light such as reducing on-axis glare and increasing chromatic contrast. This study tested the visibility hypothesis by assessing low-luminance targets under simulated blue haze conditions. Fifty-eight young healthy participants (N = 58; 18-28 years; average age = 20.45 ± 2.90, 73 % female, 33 % non-White) were measured. In each experimental session the intensity of simulated blue haze was varied while measuring the detectability of 3, 7.5, and 15 cycles-per-degree (cpd) sinusoidal gratings. MP optical density (MPOD) was measured using customized heterochromatic flicker photometry. MPOD was related to the amount of energy needed to veil the gratings at 3-cpd r (56) = 0.54, p < .001) and 7.5-cpd (r (56) = 0.36, p < .01) but not at 15-cpd (r (47) = -0.03, p = .86). Our data suggest MPOD enhances the ability to detect low and mid spatial frequency targets under blue haze conditions.