Chronotyping glaucoma patients with the Munich ChronoType Questionnaire: A case-control study.

PURPOSE: The circadian clock is entrained to light by the intrinsically photosensitive retinal ganglion cells. Loss of these cells in glaucoma, an eye disease with loss of retinal ganglion cells as its key feature, might thus result in a change in chronotype. We aimed to compare the chronotype between glaucoma patients and healthy subjects. METHODS: We sent the Munich ChronoType Questionnaire to 221 glaucoma patients (response rate 81%); controls (primary control group) were primarily their spouses. After exclusion of shift workers and participants who woke-up due to an alarm clock on days off, 159 glaucoma patients (88 early, 21 moderate, 23 severe) and 163 controls remained. We calculated chronotype as the mid-sleep on days off, corrected for workweek accumulated sleep debt (MSFsc). We compared means and variances between groups using Welch's tests and F-tests, respectively. A secondary control group was recruited from participants in a citizen-science project (n = 17073) who completed an online questionnaire. A resampling method was applied to enable an age- and gender- matched comparison with the glaucoma patients. RESULTS: Compared to the primary control group, glaucoma did not affect the mean MSFsc (controls 3:47; early, moderate, and severe glaucoma 3:40, 3:45, and 3:33, respectively [P = 0.62]). Chronotype variability seemed to increase with increasing disease severity (severe glaucoma versus controls: P = 0.023). The mean MSFsc of the secondary control group was 3:50 (95% confidence interval 3:48 to 3:52); significantly later than that of the glaucoma patients (3:40; P = 0.024). Mean MSFsc did not differ significantly between the control groups (P = 0.42). CONCLUSIONS: No clear changes were found in the chronotype as determined by sleep phase in patients with glaucoma, especially not in early and moderate glaucoma. In severe glaucoma, chronotype variability seems to increase, possibly alongside a small advancement.

Visual Performance as a Function of Luminance in Glaucoma: The De Vries-Rose, Weber's, and Ferry-Porter's Law.

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°) as a function of luminance (0.02 to 200 cd/m2). 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 < 0.001), independent of luminance. Peripherally, the difference was more pronounced at lower luminances (P = 0.007). CFF was linearly related to log luminance (Ferry-Porter). Glaucoma patients had a lower CFF compared with controls (P < 0.001), with a smaller slope of the CFF versus log luminance curve, for both the fovea (6.8 vs. 8.7 Hz/log unit; P < 0.001) and the periphery (2.5 vs. 3.4 Hz/log unit; P = 0.012). 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.

Foveal light and dark adaptation in patients with glaucoma and healthy subjects: A case-control study.

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<0.001) and 0.13 (P = 0.010) log unit lower CS plateau than controls, respectively. After dark adaptation, this difference was 0.21 (P = 0.018) and 0.30 (P<0.001) log unit, respectively. Light adaptation occurred too fast to determine an accurate light adaptation time. Dark adaptation times of glaucoma patients and controls were similar, for both the 5 (7.2 versus 5.5 minutes; P = 0.10) and the 6.5 (18.2 versus 16.6 minutes; P = 0.14) log unit step. CONCLUSION: After a sudden increase or decrease in luminance, the logCS adaptation curves of glaucoma patients are shifted downwards compared to the curves of healthy subjects. Glaucoma patients have a lower CS plateau than healthy subjects, for both light and dark adaptation; dark adaptation times are similar.

Visual complaints of patients with glaucoma and controls under optimal and extreme luminance conditions.

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 < 0.001), 22 versus 1% (p < 0.001), 32 versus 1% (p < 0.001) and 25 versus 3% (p < 0.001) for low, high, sudden decrease and sudden increase in luminance. Within the group of glaucoma patients, the frequency of complaints increased significantly with increasing disease severity at a Bonferroni-corrected p value of 0.003 for all but one (p = 0.005) luminance-specific questions that addressed extreme luminance conditions. CONCLUSION: The concept of (early stage) glaucoma as an asymptomatic disease is only valid with optimal luminance. Differences in visual complaints between glaucoma patients and controls are greater under extreme luminance conditions, especially in the dark. The fact that the cases were aware of their diagnosis could have induced bias.