The Relationship between Macular Pigment Optical Density and Retinal Straylight.

Purpose: It has been reported that individuals with higher levels of macular pigment optical density (MPOD) are less affected by disability glare, have a faster photostress recovery time and suffer less visual discomfort. Such findings add weight to the theory that the macular pigment may play a role in improving visual performance in glare. The aim of this study was to further examine this theory by examining the relationship between macular pigment optical density and estimates of retinal straylight using the Oculus Cataract Quantifier (C-Quant).Methods: 36 individuals (aged 19-40 yrs) with good visual acuity, free from ocular disease and with clear ocular media participated. MPOD was measured at 0.5 degrees eccentricity from the foveal centre using a heterochromatic flicker photometry based densitometer instrument from MacularMetrics. Retinal straylight was estimated using the Oculus C-Quant, a commercially available device which uses a psychophysical compensation comparison method. Results: Mean MPOD was 0.38 (±0.18) log units (range 0 to 0.77). Mean straylight parameter (S) was 1.05 (±0.13) log units (range 0.86 to 1.48). There was no statistically significant association between age and MPOD (r=0.03, p=0.86), age and retinal straylight (r=0.01, p=0.94) and MPOD and retinal straylight (r=0.04, p= 0.83). There was no statistically significant difference in retinal straylight levels between those individuals with MPOD levels above the average (>0.38 log units) at 0.5 degrees eccentricity and below the average (t=0.37, df=34, p=0.72).Conclusions: Retinal straylight, estimated by the Oculus C-Quant, was not significantly associated with macular pigment optical density. Further investigation on the role of macular pigment in improving visual performance in glare in the human eye is required.