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

Aim To evaluate the relationship between macular pigment optical density (MPOD) and glare disability in open-angle glaucoma. Methods A 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 degrees, 0.5 degrees and 1 degrees 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. Results Low spatial frequency (f) mCSg was significantly correlated with MPOD at 0.25 degrees(3 cycles per degree (cpd): r=0.25, p=0.04) and 0.5 degrees (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=0.02each) and prolonged PRT (p=0.02) in comparison with those without foveal involvement. The depth of central 10 degrees 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 degrees and 1 degrees: p=0.05each; 0.5 degrees: p=0.04), including those with foveal involvement (0.25 degrees: p=0.05; 0.5 degrees: p<0.01; 1 degrees: p=0.01). Conclusions Macular pigment level may be an important consideration among those experiencing disability glare in glaucoma, including those with foveal involvement. Trial registration number ISRCTN56985060, Post-results.