Evaluation of retinal nerve fiber layer progression in glaucoma: A prospective analysis with neuroretinal rim and visual field progression

Abstract

Objective: To evaluate the performance of progression detection and the rate of change of retinal nerve fiber layer (RNFL), neuroretinal rim, and visual field measurements in glaucoma. Design: Prospective study. Participants: One hundred eight eyes of 70 glaucoma patients. Methods: Patients were followed up every 4 months for at least 2.9 years (median, 3.2 years) for measurement of RNFL thickness with the Stratus optical coherence tomograph (OCT) (Carl Zeiss Meditec, Dublin, CA), neuroretinal rim area with the Heidelberg Retinal Tomograph (HRT 3; Heidelberg Engineering, GmbH, Dossenheim, Germany), and visual field with the Humphrey Field Analyzer II (Carl Zeiss Meditec). Linear regression analyses were performed between visual field index (VFI), RNFL, and neuroretinal rim measurements and age, with progression defined when a significant negative trend was detected. The agreement among structural and functional measurements was evaluated with κ statistics. The mean rate of change was estimated with linear mixed modeling. Main Outcome Measures: The agreement on progression detection and the rate of change of RNFL, neuroretinal rim, and VFI measurements. Results: A total of 1105 OCT, 1062 HRT, and 1099 visual field measurements were analyzed. The agreement of progression detection among the 3 investigations was poor (κ≤0.09). Ten eyes (9.3%; 9 patients) showed progression by average RNFL thickness, 16 (14.8%; 14 patients) by global neuroretinal rim area, and 35 (32.4%; 31 patients) by VFI. Only 1 eye (0.9%) had progression detected by all 3 methods. There were large variations in the rate of change of VFI, average RNFL thickness, and global neuroretinal rim area, with a range between -0.63% and -4.97% per year, -2.32% and -10.12% per year, and -0.61% and -8.48% per year, respectively. The respective mean rate estimates were -1.15% per year (95% confidence interval [CI], -1.56% to -0.73%), -0.70% per year (95% CI, -1.19% to -0.21%), and -1.06% per year (95% CI, -1.56% to -0.55%). Conclusions: The agreement of progression detection among RNFL, neuroretinal rim, and visual field measurements was poor, and the rate of RNFL, neuroretinal rim, and visual field progression varied considerably within and between subjects. Given this variability, interpretation of RNFL, neuroretinal rim, and VFI progression always should be evaluated on an individual basis. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. © 2011 American Academy of Ophthalmology.