Glaucoma patients commonly report increasing visual problems under low luminance or glare conditions, yet there is limited understanding of the structural basis of visual functional losses. This report examines the relationship between glaucomatous macular damage, assessed using structure-function correlation, and visual difficulty under low luminance conditions, as measured by Low Luminance Questionnaire (LLQ).

Observational cohort study.

Setting: Tertiary care referral center. Participants: A total of 252 eyes of 126 participants with mild or moderate open-angle glaucoma (24-2 mean deviation [MD] better than -12 dB) selected from a consecutive sample. Predictor: Focal and diffuse macular defects were identified based on corresponding abnormal regions on probability maps from spectral-domain optical coherence tomography (SDOCT) optic disc and macular cube scans, and 10-2 and 24-2 visual fields (VF). Main Outcome Measure: LLQ scores.

Eighty-two of the 126 (65%) better eyes (defined by 24-2 VF MD) had evidence of macular damage, while the remaining 44 did not have macular damage. Of the 82 with damage, 33 (40%) had diffuse damage and 49 (60%) had focal damage. After adjusting for 24-2 MD and age in the multivariable regression, diffuse macular damage remained a significant predictor of the LLQ subscales “difficulty with extreme lighting” (P = .0024), ‘‘difficulty with low lighting” (P = .037), and “diminished mobility”; (P = .042). In contrast, there was no significant difference in LLQ scores in any subscale between participants with focal macular damage and those without macular damage.

Mild diffuse glaucomatous macular damage, as detected by abnormal topographic regions on measures of structure and function, is associated with decreased LLQ scores.