The Glaucoma Laser Trial (GLT): 5. Subgroup differences at enrollment. Glaucoma Laser Trial Research Group

Data collected at enrollment on the 271 patients (542 eyes) who participated in the Glaucoma Laser Trial (GLT) were analyzed for subgroup differences. The subgrouping variables included four patient characteristics (race, sex, age, and history of a vascular disease) and one ocular characteristic (myopia). The strongest differences observed were between blacks and whites. As compared with the eyes of the white patients, those of the black patients had lower mean decibels per test location in the visual field (P < .001), greater mean defect (P < .001), number of abnormal test locations (P < .001), and corrected loss variance (P = .009), as well as greater cup depth (P < .001), and larger mean horizontal (P = .002) and vertical (P < .001) cup/disc ratios.