The impact of intraocular pressure fluctuations and other factors on conversion of ocular hypertension to primary open-angle glaucoma.

Abstract

To evaluate the role of intraocular pressure (IOP) fluctuations and other factors on conversion of ocular hypertension to open-angle glaucoma (OAG) within a retrospective, longitudinal cohort study. The study population included patients with ocular hypertension defined by IOP > 21mmHg with normal appearing optic discs and no visual field defect. IOP fluctuation, mean and maximum were examined in 61 eyes over a follow-up period of 36months (standard deviation (SD) 24). All patients underwent at least two 48-h IOP profiles including night-time IOP measurements in the supine position, visual field examinations, Heidelberg retina tomograph analyses (HRT) and optic disc photographs. Regression analyses were performed to demonstrate the impact of IOP parameters, myopia, sex, cup/disc ratio and visual field results on conversion to glaucoma. While IOP fluctuation and mean did not impact conversion, myopia proved to be a risk factor (HR 14.4; 95% CI: [3.9-53.0]; p ≤ 0.001). Over an average of three years, 6/61 converted to OAG. The study yielded a mean long-term IOP over all available pressure profiles of 18.1mmHg (SD 3.2) and an IOP fluctuation of 1.9mmHg (SD 1.1) within a mostly treated cohort. Conversion-free five-year rate was 59.8%. The amount of fluctuation we measured in our study sample did not result in the development of glaucoma in treated ocular hypertension patients. Myopic subjects with ocular hypertension are at a higher risk for glaucoma conversion than non-myopic ocular hypertensive subjects are.