Association between Vision-Related Difficulties in Low Light Levels and Visual Fields in Glaucoma

To determine whether self-reported visual challenges in low lighting are associated with binocular severity of 24-2 visual field (VF) loss in people with glaucoma.

A cross-sectional study.

Data from 128 participants with primary open-angle glaucoma enrolled in the longitudinal cohort "Individualised Perimetry Progression Observations in Glaucoma Study" at Lions Eye Institute, Perth, Australia, were analyzed.

Monocular VFs were merged to form an integrated visual field (IVF) using the "best location method." Visual field locations were divided into four regions: central, peripheral, superior, and inferior. The Low Luminance Questionnaire (LLQ) and Glaucoma Quality of Life-15 (GQL-15) were self-administered electronically. The associations between questionnaire scores and VF indices were assessed using linear regression, considering covariates of age, gender, lens status, and best eye visual acuity. Correlations between the composite and subscales of LLQ and GQL-15 were calculated.

Association between self-reported difficulties under low luminance and binocularly IVFs.

Visual field indices were associated with log-transformed composite LLQ scores. Piecewise linear regression identified breakpoints at 21.7 decibels (dB) (95% confidence interval [CI]: 18.1-25.3 dB) and -6.3 dB (95% CI: -2.7 to -9.9 dB) for global integrated VF mean sensitivity and total deviation, respectively. Inferior IVF defects were associated with difficulties at low light levels, especially with driving, adjusting for age, gender, lens status, and better eye visual acuity. The composite and subscales of the LLQ and GQL-15 were moderately correlated.

Self-reported difficulties at low light levels were partially explained by binocularly IVF status in people with glaucoma. The LLQ identifies difficulties at low light levels, which are not captured by the standard clinical tests.

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