The Collaborative Initial Glaucoma Treatment Study: Baseline Visual Field and Test–Retest Variability

Abstract
Purpose. To compare the baseline Collaborative Initial Glaucoma Treatment Study (CIGTS) visual field (VF) score and mean deviation (MD), investigate test–retest variability, and identify variables associated with VF loss and VF measurement variability. methods. Baseline data from a randomized clinical trial of 607 patients with newly diagnosed open-angle glaucoma were collected at 14 clinical centers. The CIGTS VF score and MD were obtained from 24-2 VF tests (Zeiss-Humphrey Systems, Dublin, CA) at two visits approximately 2 weeks apart. results. Although most baseline CIGTS VF scores showed limited field loss, 15% (91/607) of patients showed a substantial deficit (VF score >10 on a 0–20 scale). A small but significant learning effect was seen over the two baseline measures for CIGTS VF score and MD. CIGTS VF score and MD correlate highly (r = −0.93); both have high test–retest correlation (0.83 and 0.91, respectively). Variables associated with greater baseline VF loss for both CIGTS VF score and MD include (probabilities for VF only): male sex (P = 0.018), black race (P ≤ 0.0001), lower visual acuity (P ≤ 0.0001), higher intraocular pressure if more than 30 mm Hg (P = 0.0034), poor field reliability score (P ≤ 0.0001), cardiovascular disease (P = 0.015), reduced patient-reported alertness (P = 0.023), and CIGTS clinical center (P ≤ 0.0001). Predictors of increased CIGTS VF score variability include a midrange VF score (P ≤ 0.0001), first-tested eye (P = 0.0027), reduced patient-reported alertness (P = 0.0177), increasing age (P = 0.0040), current smoker (P = 0.0014), and CIGTS clinical center (P = 0.0215). conclusions. The CIGTS VF score provides a measure of VF strikingly similar to the MD. Variables associated with VF loss and VF variability may help identify patients who need greater clinical scrutiny.

This publication has 0 references indexed in Scilit: