Macular pigment and low luminance vision in the Carotenoids in Age-Related Eye Disease Study (CAREDS), an ancillary study of the Women’s Health Initiative

Abstract

Purpose : Macular pigment (MP), comprised of lutein (L) and isomers of zeaxanthin (Z), may protect the retina and thus slow decline of low luminance (rod-mediated) vision. There are few studies evaluating this possibility, and relations of MP optical density (MPOD) with rod-mediated vision have been inconsistent across age and eye disease groups. We evaluated the association of MPOD to (1) rod intercept time (RIT) and (2) low luminance questionnaire (LLQ) scores, in a longitudinal study of post-menopausal women.

Methods : This analysis includes 610 women aged 53-86 years with MPOD measured at CAREDS baseline (2001-2004, n=1804), who survived, consented to be contacted, participated in CAREDS2 (2016-2018), and completed the LLQ. Of these, 186 had RIT measured at CAREDS2 study visits. RIT was measured at 5 degrees retinal eccentricity using the AdaptDx device. MPOD was measured at 0.5 degrees (reference of 7 degrees) using customized heterochromatic flicker photometry. L/Z intake was estimated from responses to food frequency and supplement questionnaires. Age-adjusted mean LLQ scores and RIT were computed by MPOD and L/Z quintile using generalized linear models.

Results : MPOD at baseline was not associated with RIT at follow-up (mean [SD] times of 12.2 [1.4] and 10.0 [1.4] minutes in the highest and lowest quintiles, P_trend=0.49). There was little difference in LLQ score by MPOD at baseline (mean [SD] scores of 77.5 [1.5] and 78.3 [1.5] points in the highest and lowest quintiles, P_trend=0.52). Results were similar after excluding women with lens opacities or age-related macular degeneration. By contrast, women in the lowest quintile for intake of L/Z at baseline had longer RIT at follow-up compared with women in quintiles 2-5.

Conclusions : Contrary to results in younger samples, in older women neither dark adaptation speed nor self-reported low luminance vision was related to MPOD at 0.5 degrees. However, we found faster dark adaptation at follow-up in women with higher L/Z intakes at baseline, which suggests L/Z might protect against loss of rod-mediated vision over time. The lack of a relationship between MPOD and RIT may be partly explained by the light filtering properties of MP, which may have reduced the light stimulus in dark adaptation testing and resulted in longer RIT for those with higher MPOD.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.