Macular Pigment Optical Density Is Not Associated with Contrast Sensitivity When Measured with 520 nm Monochromatic Stimuli

Macular pigments (MP; lutein, zeaxanthin, and meso-zeaxanthin) filter short-wavelength light and have been linked to reduced glare and enhanced visual performance. Whether macular pigment optical density (MPOD) is associated with contrast sensitivity (CS) under conditions of minimal MP absorption remains unclear. Fifty-two adults (mean age = 23.5 ± 8.0 years; range = 18-58 years; 85% < 25 years) participated. MPOD was measured using customized heterochromatic flicker photometry. CS was assessed monocularly in the same eye at five spatial frequencies (1.6, 3.2, 8, 16, and 24 cycles/degree), using a custom optical system with narrowband 520 nm laser stimuli. No significant correlations were found between MPOD and CS at any spatial frequency (all |r| ≤ 0.08, all p ≥ 0.59), including when individual area estimates were made for each participant's curve (area under the logged CSF). Separate partial correlations controlling for iris lightness or habitual visual correction were also non-significant. Although MP has been shown to be related to CS when measured under glare or blue haze conditions, these findings suggest that when filtering by MP is minimized, direct effects on CS, especially on the young healthy eye, are likely minimal.