Baseline Intraocular Pressure, Visual Function, and Disc Hemorrhage in the Low–Pressure Glaucoma Treatment Study

Abstract

Abstract: : Purpose: To evaluate the associations between baseline IOP, disc hemorrhage (DH) and visual field (VF) parameters in the Low–pressure Glaucoma Treatment Study (LoGTS). Methods: LoGTS is a randomized, double–masked trial to evaluate VF stability in patients randomized to topical twice–daily brimonidine tartrate 0.2% versus twice daily timolol maleate 0.5%. Low–pressure glaucoma (LPG) was defined as open angle glaucoma with a glaucomatous VF defect in at least one eye on Humphrey 24–2 full–threshold standard automated perimetry and all known IOP < 22 mmHg. Baseline measurements included untreated diurnal IOP curve (8 am, 10 am, 12 pm, and 4 pm), central corneal thickness (CCT) measurements, and stereophotography. Baseline disc photographs were assessed for DH by three masked observers. The relationship of ocular and non–ocular parameters in the DH and non–DH groups was assessed. Results: 380 eyes (190 patients) were enrolled (mean age 64.9 ±10.7 yrs) with an average VF mean deviation (MD) of –5.7 ± 4.1 dB. DH was present in one eye of 24 patients (12.6%) at baseline and was more common in women (p=0.02). DH and non–DH eyes were similar with respect to age (p=0.4), MD (p=0.3), PSD (p=0.6), peak IOP (p=0.7), diurnal fluctuation (peak IOP–trough IOP) (p=0.1), mean diurnal IOP (p=0.7), and CCT (p=0.1). There were no differences in the above parameters between the DH and non–DH eyes of the same patient (all p > 0.5). Conclusions: DH was common at the time of entry into the LoGTS study and was unrelated to IOP, CCT and the extent of visual field injury. A higher frequency of DH was observed in women.

Keywords: clinical (human) or epidemiologic studies: risk factor assessment • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled • intraocular pressure