With glare testing, the clinician attempts to measure the degree of visual impairment caused by the presence of a light source located in the patient’s visual field. Testing can be done with a nonprojected eye chart in ambient light conditions or with a projected eye chart and an off-axis bright light directed at the patient. Various instruments are available to standardize and facilitate this measurement. Patients with significant cataracts commonly show a decrease of 3 or more lines under these conditions, compared with results obtained when visual acuity is tested in a darkened room. It is best to perform this assessment prior to dilation. Glare testing performed after dilation must be adjusted to account for the change in visual acuity after dilation; the results may be less accurate, especially in patients with a PSC.
Wiggins MN, Irak-Dersu I, Turner SD, Thostenson JD. Glare testing in patients with cataract after dilation. Ophthalmology. 2009;116(7):1332–1335.
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.