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PURPOSE. To determine whether the De Vries-Rose, Weber's, and Ferry-Porter's law, which describe visual performance as a function of luminance, also hold in patients with glaucoma.METHODS. A case-control study with 19 glaucoma patients and 45 controls, all with normal visual acuity. We measured foveal and peripheral contrast sensitivity (CS) using static perimetry and foveal and peripheral critical fusion frequency (CFF; stimulus diameter 1 degrees) as a function of luminance (0.02 to 200 cd/m(2)). ANOVA was used to analyze the effect of glaucoma and luminance on CS and CFF; analyses were adjusted for age and sex.RESULTS. Foveally, logCS was proportional to log luminance at lower luminances (de Vries-Rose) and saturated at higher luminances (Weber); glaucoma patients had a 0.4 log unit lower logCS than controls (P CONCLUSIONS. Even in apparently intact areas of the visual field, visual performance is worse in glaucoma patients than in healthy subjects for a wide range of luminances, without a clear luminance dependency that is consistent across the various experiments. This indicates impaired signal processing downstream in the retina and beyond, rather than an impaired light adaptation in the strictest sense.

Glaucoma is traditionally considered an asymptomatic disease until later stages. However, questionnaire studies revealed visual complaints related to various tasks, especially under extreme luminance conditions (such as outdoor at night on an unlit road or outside in the sun). We measured contrast sensitivity (CS) over a luminance range of 6 log units spanning the scotopic to photopic range and we aimed (1) to determine whether Weber’s law also holds under extremely high luminance conditions and (2) to compare CS as a function of spatial frequency and luminance between glaucoma patients and healthy subjects. We included 22 glaucoma patients and 51 controls, all with normal visual acuity. For the second aim, we used a subgroup of 22 age-similar controls. Vertically oriented sine-wave gratings were generated with a projector-based setup (stimulus size 8x5 degrees). CS was measured monocularly at 1, 3, and 10 cycles per degree (cpd); mean luminance ranged from 0.0085 to 8500 cd/m2. ANOVA was used to analyze the effect of glaucoma, luminance, and spatial frequency on logCS. In controls, Weber’s law held for 3 and 10 cpd; for 1 cpd, CS dropped above 1000 cd/m2 (P = 0.003). The logCS versus log luminance curves did not differ grossly between patients and controls (P = 0.14; typically 0–0.2 log units); the difference became larger with decreasing luminance (P = 0.003) but did not depend clearly on spatial frequency (P = 0.27). We conclude that differences between glaucoma and healthy were relatively modest for the spatially redundant, static stimulus as used in the current study.

PURPOSE To determine (i) whether, compared to controls, visual complaints of glaucoma patients are more pronounced under extreme luminance conditions than in the optimal luminance condition and (ii) whether complaints belonging to different extreme luminance conditions are associated. METHODS We developed a luminance-specific questionnaire and sent it to 221 glaucoma patients (response rate 81%); controls (182) were primarily their spouses. Median (interquartile range) mean deviation of the visual field of the patients' better eye was -4.5 (-10.7 to -1.9) dB. Questions were addressing visual performance under five luminance conditions: presumed optimal (outdoor on a cloudy day), low, high, sudden decrease and sudden increase. We compared percentages of patients and controls who reported visual complaints while performing activities under different luminance conditions. RESULTS Percentages of patients and controls with visual complaints were 4 versus 0% (p = 0.02) for optimal luminance and 48 versus 6% (p

Introduction To determine whether foveal light and dark adaptation are affected in glaucoma. Methods Case-control study with 23 glaucoma patients and 51 controls. Light and dark adaptation were measured twice. After 10 minutes pre-adaptation to 0.0032 cd/m2, the background luminance increased stepwise to 320 (5 log unit step) or 10,000 cd/m2 (6.5 log unit step) for 10 minutes, then it decreased back to 0.0032 cd/m2 for 30 minutes. Foveal contrast sensitivity [CS]) as a function of time was determined using a 1.15 degree increment. Time resolution of the experiments was 30 seconds. Multiple linear regression was used to analyse the effect of glaucoma on the CS plateau and adaptation time (time to reach the plateau minus 3 dB); analyses were adjusted for age and gender. Results After light adaptation to 320 and 10,000 cd/m2, glaucoma patients had a 0.22 (P