Glaucoma and glare

To determine whether a purpose-built glare tester, in combination with new glare-specific questions, can better assess glaucoma patients' experience of glare and visual disability than visual acuity (VA) or visual fields alone.

Consecutive patients attending for visual fields in a single glaucoma clinic from 03/06/2019-01/11/2019 underwent VA assessment using a Brightness Acuity Tester as a glare source, examination for media opacities, and completed the VFQ-25 with four additional glare-related questions. One hundred and sixteen eyes (64 patients) were included for analysis. The amount of disability glare (VA reduction due to glare) was compared according to presence/absence of media opacity and glaucoma severity. Subjective glare symptoms were compared with objective disability glare measurement using a Bland-Altman plot.

Patients with advanced-severe glaucoma had significantly worse disability glare than those with mild-moderate glaucoma. VA reduction due to glare from mild-moderate to acute-severe glaucoma (mean -3.4 letters, P = 0.01, CI -0.8, -6.0) was of almost identical magnitude to that due to presence of any media opacity (mean -3.3 letters, P = 0.03, CI -0.4, -6.2). There was a trend towards greater disability glare in more symptomatic patients, with good agreement between subjective and objective glare measurements for those with few glare signs or symptoms, but progressively more variation either side of agreement as either measurement worsened.

Glaucoma is associated with objective and subjective acuity reduction in the presence of glare. We demonstrated an increase in disability glare in patients with more severe glaucoma. The worse the glare symptoms or signs, the more variable the agreement between objective and subjective assessments.