Macular Pigment Reflectometry: Developing Clinical Protocols, Comparison with Heterochromatic Flicker Photometry and Individual Carotenoid Levels

The study was designed to: (1) Analyze and create protocols of obtaining measurements using the Macular Pigment Reflectometry (MPR). (2) To assess the agreement of MPOD measurements obtained using the heterochromatic flicker photometry (MPS II) and MPR. (3) To obtain the lutein and zeaxanthin optical density obtained using the MPR in the central one-degree of the macula. The measurements were performed using the MPR and heterochromatic flicker photometry. The MPR measurements were performed twice without pupillary dilation and twice following pupillary dilation. The MPR measurements were performed for a 40-s period and the spectrometer signal was parsed at different time points: 10–20, 10–30, 10–40, 20–30, 20–40, and 30–40 s. The MPR analyzes the high-resolution spectrometer signal and calculates MPOD, lutein optical density and zeaxanthin optical density automatically. The MPR-MPOD data was compared with MPPS II-MPOD results. The MPR-MPOD values are highly correlated and in good agreement with the MPS II-MPOD. Of the various parsing of the data, the data 10–30 interval was the best at obtaining the MPOD, lutein, and zeaxanthin values (8–12% coefficient of repeatability). The lutein to zeaxanthin ratio in the central one-degree of the macula was 1:2.40. Dilation was not needed to obtain the MPOD values but provided better repeatability of lutein and zeaxanthin optical density. MPR generates MPOD measurements that is in good agreement with MPS II. The device can produce lutein and zeaxanthin optical density which is not available from other clinical devices.

Is the Helmholtz–Kohlrausch Effect More Robust in Women?

For gray or achromatic objects, brightness is a relatively simple transformation where very low luminance levels are perceived as black and higher levels are perceived as white. For chromatic objects, the transformation is more complex, depending on color purity as well. This influence of color purity on a color’s perceived brightness is a well-established phenomenon known as the Helmholtz–Kohlrausch (H-K) effect. We investigated gender differences in the H-K effect by measuring brightness (via direct brightness matching [DBM]) and luminance (via heterochromatic flicker photometry [HFP]) at five wavelengths (450, 520, 560, 580, and 650 nm) perceived as blue, green, green-yellow, yellow, and red hues. We compared DBM/HFP ratios between 13 males and 18 females. Based on previous evidence of a female advantage in chromatic processes, we hypothesized that DBM/HFP ratios would be higher in female subjects. While HFP measures were essentially the same between male and female subjects, DBM measures and DBM/HFP ratios were significantly higher for female subjects than males. There were no significant effects of contraceptive use based on a post hoc comparison. We also derived simple models of brightness as a function of luminance and saturation, which further suggest gender dimorphism in the H-K effect.

Predictors of macular pigment and contrast threshold in normolipemic subjects aged 45-65

Objective: The dietary carotenoids lutein and zeaxanthin are transported in the bloodstream by lipoproteins and selectively captured in the retina where they constitute macular pigment. There are no lutein and zeaxanthin dietary intake recommendations nor desired blood/tissue concentrations for the general population. The aim of this study was to determine the lutein and zeaxanthin dietary intake, their serum concentrations, lipid profile, macular pigment optical density (MPOD) and the contrast sensitivity (CT), as visual outcome in normolipemic subjects age 45-65 (n=101). Methods: MPOD, L and Z in serum and dietary intake were determined using heterochromatic flicker photometry, high-performance liquid chromatography and 3-day food records. CT was measured with the CGT-1000 Contrast Glaretester at six stimulus sizes, with and without glare. Results: Lutein and zeaxanthin serum concentrations (median): 0.361 and 0.078 µmol/L. Lutein+zeaxanthin intake: 1.1 mg/d (median). MPOD: 0.34 du. Lutein+zeaxanthin intake correlates with their serum concentrations (ρ=0.333, p =0.001), which in turn correlates with MPOD (ρ=0.229, p =0.000) and with the fruit and vegetable consumption (ρ=0.202, p =0.001), but not with the lutein+zeaxanthin dietary intake. HDL-cholesterol correlated with lutein+zeaxanthin serum (ρ=0.253, p =0.000) and with CT under glare conditions (ρ range: 0.016–0.160). MPOD predictors: serum lutein+zeaxanthin, lutein+zeaxanthin/HDL-cholesterol and HDL-cholesterol (R 2 =15.9%). CT predictors: MPOD and sex (β coefficients ranges: -0.950,-0.392; -0.134,-0.393, respectively). Conclusion: There were correlations at all points in time in this sequence between lutein+zeaxanthin intake and the visual outcome and, HDL-cholesterol played a relevant role.

Skin and Macular Carotenoids and Their Implications for Cognitive Control and Achievement in Children (OR05-08-19)

Objectives Carotenoids are plant pigments that accumulate across several tissues including the macula and skin. However, the relationship between carotenoid deposition in retina and skin is unknown in children. Understanding these interrelationships is important, given that evidence indicates that carotenoid status is a marker of cognitive health in childhood. Importantly, the selectivity of cognitive function to carotenoids in different tissues remains understudied. The present work investigated associations between retinal and skin carotenoids and their implications for children's cognitive function and achievement. Methods Children 7–12 years old (N = 50) participated in the study. Retinal carotenoid status, i.e., macular pigment optical density (MPOD), was assessed using heterochromatic flicker photometry. Skin carotenoids were assessed using reflection spectroscopy at the fingertip using the Veggiemeter. Academic achievement was assessed using the Woodcock Johnson IV test and a modified Eriksen flanker task to assess children's ability for selective attention or interference control. Results There was a significant positive correlation between skin and retinal carotenoid levels (rs = 0.29, P = 0.02). Skin carotenoids were positively related to reading (rs = 0.42, P = 0.001) and math scores (rs = 0.34, P = 0.009). However, skin carotenoids were not significantly related to flanker interference scores (p's > 0.05). On the other hand, MPOD was positively related to reading (rs = 0.25, P = 0.04) but not math (rs = 0.12, P = 0.20). Further, MPOD was inversely related to flanker interference scores for reaction time (rs = −0.29, P = 0.02) and accuracy (rs = −0.28, P = 0.03), indicating that children with higher retinal carotenoids exhibited superior ability to maintain cognitive control performance when faced with greater task demands. Conclusions These findings demonstrate that carotenoid levels in skin and retina are correlated in children. These findings further suggest that carotenoid status in children is associated with cognition, perhaps selectively across site of accumulation and cognitive domains. Funding Sources This work was supported by funds provided by the Egg Nutrition Center.

Single Nucleotide Polymorphisms in BCO1 and CD36 Are Related to Macular Pigment Among Children (OR05-04-19)

Objectives Xanthophyll carotenoids in the retina have been linked to visual and cognitive health. While genetic variations in genes related to carotenoid cleavage (e.g., beta-carotene-15,15′-monooxygenase [BCO1/BCMO1]) and xanthophyll transport (e.g., Cluster Determinant 36 [CD36]) proteins have been shown to influence MPOD in adults, it is unknown whether these relationships are evident in childhood. We examined the influence of genetic variation (single nucleotide polymorphisms [SNPs]) in BCO1 and CD36 on MPOD in 7–10 year-olds (N = 134). Methods Macular pigment optical density (MPOD) was assessed using heterochromatic flicker photometry. DNA was extracted from saliva samples and genotyped for six tag-selected SNPs, identified by previous work among adults. Ancestry informative markers (AIMs) were genotyped to account for ethnic heterogeneity. Dietary lutein and zeaxanthin (L + Z) was assessed using 3d food records among a subsample (N = 82). Results Minor allele frequencies of BCO1-rs7501331 (T), CD36-rs1527483 (T), CD36-rs3173798 (C) were 0.194, 0.090 and 0.213, respectively. In the partially adjusted (AIMs, age, sex, BMI %tile) models, three of the six SNPs were associated with MPOD. Carriers of the BCO1-rs7501331 T allele had significantly lower (∼18%) MPOD than the CC homozygotes (P = 0.042). Minor allele (T) carriers of CD36-rs1527483 exhibited lower MPOD (∼23%) than CC homozygotes (P = 0.043). CD36-rs3173798 C allele carriers had ∼32% lower MPOD than those with the TT genotype (P < 0.001). Applying the fully adjusted models (AIMs, age, sex, BMI %tile, L + Z) among the subsample revealed that L + Z was a significant predictor of MPOD (P = 0.04); however, CD36-rs3173798 was the only SNP associated with MPOD (P = 0.009). Conclusions MPOD in children is influenced by individual genetic variation. Specifically, variation in the CD36 gene, responsible for a protein involved in transport of lipids and carotenoids, was robustly associated with macular pigment in children. These findings have implications for future recommendations for dietary or supplemental approaches to improving xanthophyll status among children. Funding Sources NIH (HD069381); Abbott Nutrition (2012-04608). iTOPP (2011-67001-30101). USDA AFRI (2015-68001-23248) and the Department of Human Development and Family Studies.

Macular pigment is associated with glare-affected visual function and central visual field loss in glaucoma

AimTo evaluate the relationship between macular pigment optical density (MPOD) and glare disability in open-angle glaucoma.MethodsA cross-sectional analysis of baseline data (88 subjects; median age, 67 (range 36–84) years) collected during the Macular Pigment and Glaucoma Trial (ISRCTN registry number: 56985060). MPOD at 0.25°, 0.5° and 1° of retinal eccentricity was measured using customised heterochromatic flicker photometry. Mesopic contrast sensitivity with glare (mCSg), photostress recovery time (PRT) and self-reported glare symptoms were evaluated. Fourier-domain optical coherence tomography was used to analyse ganglion cell complex (GCC) and identify foveal involvement.ResultsLow spatial frequency (f) mCSg was significantly correlated with MPOD at 0.25°(3 cycles per degree (cpd): r=0.25, p=0.04) and 0.5° (3 cpd: r=0.23, p=0.04) of retinal eccentricity. Those with foveal GCC loss exhibited lower MPOD, had worse low spatial fmCSg (1.5 cpd and 3 cpd, p=0.02 each) and prolonged PRT (p=0.02) in comparison with those without foveal involvement. The depth of central 10° field loss was related to MPOD at all eccentricities (p<0.01 for all). Those who reported glare symptoms had a significantly lower MPOD at all retinal eccentricities (0.25° and 1°: p=0.05 each; 0.5°: p=0.04), including those with foveal involvement (0.25°: p=0.05; 0.5°: p<0.01; 1°: p=0.01).ConclusionsMacular pigment level may be an important consideration among those experiencing disability glare in glaucoma, including those with foveal involvement.Trial registration numberISRCTN56985060, Post-results.