Abstract
Purpose: :
1) To characterize changes in intraocular pressure (IOP) and perimetric Mean Deviation (MD) in newly diagnosed patients with open angle glaucoma, randomized to no initial treatment in the Early Manifest Glaucoma Trial (EMGT) and, 2) to evaluate factors associated with progression in this group of controls.
Methods: :
Natural history was assessed among control patients followed for ≥ 6 years or progressed by EMGT criteria within 6 years (n= 118). Follow–up data were considered only until time of treatment, if any. The rate of change was determined by calculating individual regression slopes and then summarized. Cox proportional hazard analyses evaluated associations with progression and were expressed by hazard ratios (HR) and 95% confidence intervals (95% CI).
Results: :
At baseline, the median IOP was 20.75mmHg. IOP was stable up to 6 years (median decrease of 1.0 mmHg, 0.02mmHg/yr) among the untreated patients. IOP changed annually by < 0.5mmHg for about half (57.6% (68/118)) of control patients, increased by ≥0.5mmHg for 21.2% (25/118) and decreased by ≥ 0.5mmHg for 21.2% (25/118). Of all factors studied, only exfoliation was associated with more change in IOP (1.50mmHg/yr more; p=0.02). Median baseline MD was –3.37 dB and worsened overall (median decrease of 2.37dB, 0.45dB/yr). For about 1/3 (34.7%) of patients, MD decreased annually by at least 0.75dB, with 10% worsening by 2.23dB/yr and 5% by 4.51dB/yr. Annual decreases in MD were associated with higher IOP (0.98dB worse with IOP >21mmHg; p=0.01)), older age (0.75dB worse with age >68 years; p=0.03) and exfoliation at baseline (2.58dB worse; p=0.02). Eighty (67.8 %) of these control patients progressed within 6 years. Baseline factors predictive of progression were exfoliation (HR=2.06(1.09–3.90)), higher IOP (HR=1.99 (1.23–3.22)), having 2 eligible eyes (HR=1.82 (1.07–3.09)), older age (HR=1.77(1.11–2.82)) and worse MD (HR=1.64 (1.03–2.63)). During follow–up the % of visits with disc hemorrhages (HR=1.03 (1.01–1.04) per percent higher) increased progression risk.
Conclusions: :
Most of these untreated patients with early glaucoma progressed within 6 years. IOP levels did not vary significantly over time, except in the presence of exfoliation. MD tended to worsen, but the degree varied with baseline IOP, age and exfoliation. Similar predictive factors were reported previously when all EMGT patients were considered. This suggests that factors predictive of progression are similar regardless of treatment status.
Keywords: clinical (human) or epidemiologic studies: natural history