The Advanced Glaucoma Intervention Study (AGIS): 14. Distinguishing Progression of Glaucoma from Visual Field Fluctuations
Year of Publication
Kim, J; Dally, L; Ederer, F; Gaasterland, D; Van Veldhuisen, P; Blackwell, B; Sullivan, E; Prum, B; Shafranov, G; Beck, A; Spaeth, G; AGIS Investigators
Adult; Aged; Disease Progression; Female; Follow-Up Studies; Glaucoma- Open-Angle; Male; Middle Aged; perimetry; Probability; Recurrence; Research U.S. Gov PHS; Vision Disorders; Visual Fields
PURPOSE: To determine the least worsening of a visual field (VF) and the least number of confirming tests needed to identify progression of glaucomatous VF defects. DESIGN: Cohort study of participants in a clinical trial. PARTICIPANTS: Seven hundred fifty-two eyes of 565 patients with advanced glaucoma. METHODS: Visual field tests were quantified with the Advanced Glaucoma Intervention Study (AGIS) VF defect score and the Humphrey Field Analyzer mean deviation (MD). Follow-up was 8 to 13 years. MAIN OUTCOME MEASURES: Two measures based on the AGIS VF defect score: (1) sustained decrease of VF (SDVF), a worsening from baseline by 2 (alternatively, 3 or 4) or more units and sustained for 2 (alternatively, 3) consecutive 6-month visits and (2) after the occurrence of SDVF, the average percent of eyes with worsening by 2 (alternatively, 3 or 4) or more units from baseline. Two similar measures based on MD. RESULTS: Based on the original AGIS criteria for SDVF (a worsening of 4 units in the AGIS score sustained during 3 consecutive 6-month visits), 31% of eyes had an SDVF. The percent of eyes with a sustained event increases by approximately 10% when either the minimum number of units of field loss or the minimum number of 6-month visits during which the loss is sustained decreases by 1. During 3 years of follow-up after a sustained event, a worsening of at least 2 units was found in 72% of eyes that had a 2-visit sustained event. The same worsening was found in 84% of eyes that had a 3-visit sustained event. Through the next 10 years after a sustained event, based on worsening of 2, 3, or 4 units at 2 or 3 consecutive tests, the loss reoccurred, on average, in >/=75% of study eyes. Results for MD are similar. CONCLUSIONS: In patients with advanced glaucoma, a single confirmatory test 6 months after a VF worsening indicates with at least 72% probability a persistent defect when the worsening is defined by at least 2 units of AGIS score or by at least 2 decibels of MD. When the number of confirmatory tests is increased from 1 to 2, the percentage of eyes that show a persistent defect increases from 72% to 84%.