The macular pigment is an accumulation of the dietary carotenoids lutein, zeaxanthin, and mezo-zeaxanthin throughout the retina but principally in the region corresponding to the central 15◦of the visual field. Since the macular pigment absorbs light in the 400 to 520 nm range, it is a spectral filter over the photoreceptors, attenuating the incident light in the macular pigment absorption spectrum. The between-subject average macular pigment optical density is about 0.2 to 0.6 log units with a range reportedly between 0 to 1.5 log units depending on the sampled population. Some people can increase their macular pigment optical density by increasing their consumption of lutein and zeaxanthin, which may have consequences for visibility in degraded visual environments (DVE). Specifically, nutritional and dietary interventions have produced statistically significant enhancements in such visual tasks as low contrast target detection, contrast sensitivity, glare resistance and recovery, etc. The question is whether these changes are operationally meaningful. The present paper models macular pigment optical density effects on mesopic vision using the current CIE recommendation for scotopic- to-photopic weighting to define mesopic spectral sensitivity. Since the scotopic spectrum overlaps that of the macular pigment more than does the photopic spectrum, the effect of the macular pigment increases as vision transitions from photopic-to-scotopic conditions. Our mesopic visibility model, an elaboration of our previously reported photopic and scotopic models, captures this effect and applies it to current light sources common in cultural lighting and to reflectance spectra we previously evaluated and reported.