Natural History of Intraocular Pressure in the Early Manifest Glaucoma Trial A 6-Year Follow-up

Objectives: To characterize intraocular pressure (IOP) changes during 6 years of follow-up among patients with early, newly diagnosed glaucoma randomized to no initial treatment in the Early Manifest Glaucoma Trial (control group) and to evaluate factors associated with IOP changes in this group. Methods: Early Manifest Glaucoma Trial control patients, aged 50 to 80 years at baseline, were followed up for 6 years or to the time of progression, when treatment could be initiated. After baseline, patients were followed up every 3 months with comprehensive ophthalmologic examinations, including Goldmann applanation tonometry. Change in IOP over 6 years was assessed by linear regression analyses. Results: At baseline, the median IOP of this cohort (N = 118) was 20.8 mm Hg and was higher for the 15 patients with exfoliation glaucoma (24.0 mm Hg vs 20.0 mm Hg for others; P = .005). In patients without exfoliation glaucoma, IOP remained stable during follow-up (median IOP change of -0.01 mm Hg/y; interquartile range, 0.85 mm Hg/y). In comparison, patients with exfoliation glaucoma showed a significantly larger median change of 0.96 mm Hg/y (interquartile range, 3.11 mm Hg/y) (P = .004). In the overall cohort, the only factor related to IOP change was exfoliation glaucoma (P < .001). Among patients without exfoliation glaucoma, no factors were associated with IOP change. Conclusions: In patients with early glaucoma, IOP remained stable without treatment during a 6-year period, regardless of baseline IOP, except for patients with exfoliation glaucoma, where IOP increased by almost 1 mm Hg annually. No factors, aside from exfoliation glaucoma, were related to longitudinal changes in IOP. These new natural history data may be useful in guiding management decisions for glaucoma treatment, particularly in patients with early disease or with exfoliation glaucoma.