Quantitative assessment of diffuse retinal nerve fiber layer atrophy using optical coherence tomography: diffuse atrophy imaging study

Abstract

Purpose: To evaluate quantitatively the degree of diffuse retinal nerve fiber layer (RNFL) atrophy using Stratus optical coherence tomography (OCT).

Design: Prospective, cross-sectional study.

Participants: One hundred two eyes of 102 patients with diffuse RNFL atrophy and 102 healthy eyes of 102 age-matched subjects were enrolled in the Diffuse Atrophy Imaging Study.

Methods: Two experienced observers graded RNFL photographs of diffuse RNFL atrophy eyes using a previously reported standardized protocol with a 4-level grading system. Readings were taken from the superior and inferior RNFL areas. The OCT-measured RNFL thickness parameters were compared among normal eyes and diffuse atrophy subgroups. Area under the receiver operating characteristic curves (AROCs) was calculated for various OCT RNFL parameters.

Main outcome measures: Average and segmental (4 quadrants and 12 clock-hours) OCT-measured RNFL thicknesses and AROCs for various OCT parameters.

Results: For superior and inferior RNFL areas, diffuse atrophy grading by 2 observers agreed in 82.5% and 83.3% of cases, respectively, with a substantial agreement (kappa value = 0.760 [P < 0.001] and 0.777 [P < 0.001]). Significant differences were observed in RNFL thickness among normal and all diffuse atrophy subgroups, especially in the 7 and 11 o'clock sectors (P < 0.0001). The OCT RNFL thickness measurements decreased with increasing severity of RNFL damage. The 7 and 11 o'clock sectors showed the highest AROCs for discrimination of mild RNFL atrophy from normal eyes (0.972 and 0.979, respectively).

Conclusions: The OCT RNFL thickness parameters showed excellent quantitative correlation with the degree of diffuse RNFL atrophy. Our results suggest that Stratus OCT may serve as a useful adjunct in accurately and objectively assessing the degree of diffuse RNFL atrophy.