Mean Intraocular Pressure and Progression Based on Corneal Thickness in Patients with Ocular Hypertension

Abstract

Purpose To determine the incidence of glaucomatous progression at mean intraocular pressure (IOP) levels in patients with ocular hypertension (OHT). Methods A retrospective, multicentre, cohort analysis of 230 OHT patients with 5 years of follow-up evaluated for risk factors associated with progressive optic disc and visual field loss to determine the incidence of glaucomatous progression. Results Forty percent of patients with IOPs >= 24 mmHg, 18% of patients with IOPs of 21-23 mmHg, 11% of patients with IOPs with 18-20 mmHg, and 3% of patients with IOPs of <= 17 mmHg progressed to glaucoma. The mean IOP was 19.8 +/- 2.4 mmHg in the stable group and 21.7 +/- 2.6 mmHg in the progressed group (P = 0.0004). The highest average peak IOP was 23.4 +/- 4.0 mmHg in the stable group and 25.2 +/- 3.1 mmHg in the progressed group (P = 0.006). Based on the pachymetry values for central corneal thickness, patients with thinner corneas more often progressed to glaucoma (P<0.0001). A multivariant regression analysis to determine risk factors for progression was positive primarily for higher peak IOPs, older age, male gender, argon laser trabeculoplasty, visual acuity >= 20/50, and no topical medical therapy or beta-blocker therapy prior to the study. Conclusions IOP reduction within the normal range over 5 years of follow-up reduces the chance of progression to primary open-angle glaucoma in OHT patients.