Abstract
To determine the rate of visual field (VF) loss before and after the diagnosis of primary open angle glaucoma (POAG) in the Ocular Hypertension Treatment Study (OHTS).
Pre-specified analyses of data collected prospectively in a clinical trial with extended follow-up.
Participants who developed POAG during OHTS 1 and 2 (February 1994 to December 2008) constitute an inception cohort. Follow-up data were collected in OHTS 3 (January 2016 to April 2019). Analyses were performed from July 2021 to August 2022.
In OHTS 1 and 2, visual field (VF) tests were performed every 6 months and stereoscopic optic disc photographs were taken every 12 months. These tests were repeated in OHTS 3.
Slopes of mean deviation (MD) were calculated by linear regression for all eyes in OHTS 1 and 2: eyes that did not develop POAG, eyes that developed optic disc POAG only, and eyes that developed VF POAG with/without optic disc POAG. Mean pre- and post-POAG slopes were calculated for eyes with a minimum of 5 VFs for each period.
Mean age at diagnosis of POAG was 66.4 ± 9.5 SD years (n= 282 participants), (56%) were male, 61% were White non-Hispanic and 32% were Black not Hispanic by self-report. The post-POAG slope was -0.40 ± 0.64 SD dB/year for all POAG eyes (n=280 eyes), -0.19 ± 0.4 SD dB/yr. for optic disc POAG only eyes (n=112 eyes), and -0.54 ± 0.7 SD dB/yr. for VF POAG eyes with or without optic disc POAG (n=168 eyes). Among the VF POAG eyes, 69 (41%) had post-POAG MD slopes worse than or equal to -0.5 dB/year, 35 (21%) had slopes worse than or equal to -1.0 dB/year, and 9 (5.4%) had slopes worse than or equal to -2.0 dB/year.
Some participants in OHTS had rapid rates of VF loss in one or both eyes despite being followed in a clinical study. This emphasizes that ocular hypertensive patients require careful follow-up, especially those at high risk of developing POAG to ensure early diagnosis and appropriate treatment of POAG.