Beirings et al. from the Netherlands studied visual complaints of glaucoma patients vs. controls in both optimal as well as challenging lighting conditions, defined as: ideal, low, high, sudden decrease & sudden increase in the level of lighting. This was a questionnaire study based on the subjective reporting of patients, while their spouses/neighbors served as controls. A high (81%) response rate was achieved. The percentage of subjects with complaints were (for glaucoma/ normal, respectively): optimal lighting: 4/0, low lighting: 48/6, high: 22/1, sudden decrease: 32/1, sudden increase: 25/3; all comparisons were statistically significant. Complaints were highly correlated with the severity of the glaucoma, as judged by the visual field mean deviation. It may be concluded that for a glaucoma patient the most disturbing lighting environment, from worst to best, would be: low light, sudden decrease, sudden increase, high lighting and finally optimal.
The authors conclude that even early glaucoma patients reported complaints in non-ideal lighting conditions, more so in the dark, leading them to conclude that early glaucoma might not be an asymptomatic disease.
Early glaucoma might not be an asymptomatic disease
Drawbacks of this study include the subjective, questionnaire, nature of the study and the fact that patients and controls were not tested under standardized conditions. Knowing one's diagnosis might have introduced some bias into the study. One take-home message might be that even an early glaucoma patient with normal visual acuity and only mild VF changes might, contrary to the current dogma, not be asymptomatic under less than ideal lighting conditions.