Abstract
Abstract: :
Purpose:To explore the feasibility of using a single test to monitor glaucomatous progression by examining the concordance between visual field progression and Heidelberg Retina Tomograph (HRT) sector rim area (RA) progression. Methods:198 ocular hypertensive (OHT) subjects (median age 60.2 yrs, range 32.0–78.9; median follow–up 6.1 yrs, range 2.3–7.2) and 21 normal controls (median age 65.0 yrs, range 41.3–77.4; median follow–up 5.3 yrs, range 3.1–6.8) were selected for analysis from a group of patients followed prospectively for progression. Each subject had Humphrey visual field testing and HRT imaging on > 5 occasions; 1 eye per subject was analyzed. HRT images were analyzed using a 320µm reference plane. Linear regression of RA over time was performed for each disc sector. Variability was estimated from the residual standard deviation (RSD). Subjects were classified as having high or low variability based on a 50th centile RSD cut–off. Progression was defined as a significant negative slope >1% of baseline RA/year (p<0.01, low variability series and p<0.002, high variability series) in at least one disc sector. Visual fields were analyzed by pointwise linear regression of sensitivity over time. Progression was defined according to the three–omitting criterion (Gardiner SK – IOVS 2002). Results:14 (7.1%) OHT subjects progressed by both visual field and RA. A further 33 (16.7%) OHT subjects progressed by RA compared to 19 (9.6%) by visual field alone. Of the 14 subjects showing agreement, 9 demonstrated congruity between respective rim and field sectors. 1 control subject (4.8%) progressed by RA and 1 (4.8%) by field with no agreement. A significant sector RA improvement (without progression) was detected in 14 of the 219 subjects (6.4 %). Significant field improvement was detected in 4 subjects (1.8%). Conclusions:A poor level of agreement was demonstrated in this study. Specificity may be estimated at 95.2% and 93.6%, respectively, from the (assumed) false–positive progressor rate in controls and the (assumed) false–positive improvement in the OHT subjects. The high specificity suggests that most of those progressing were true–positives. The poor agreement indicates failure of either test in the majority of progressing patients. It is recommended that both structure and function are monitored in OHT patients to provide the greatest chance of detecting progression.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • perimetry • optic disc