Enhanced Detection of Glaucoma Progression using WidefieldSwept-Source Optical Coherence Tomography.

Abstract

Purpose: To examine the effectiveness of evaluating widefield swept-source optical coherence tomography (OCT) scans for detecting glaucoma progression compared with conventional circumpapillary retinal nerve fiber layer (cpRNFLT) measurements.

Design: Longitudinal study.

Participants: One-hundred and fifty-six eyes with glaucoma from 115 participants.

Methods: This study included individuals seen over ≥2 visits that were 12 months apart, and who were also scheduled for retest visits within ≤1 month at the baseline and 12-month visits. A circumpapillary circle scan on spectral-domain OCT and a widefield 15×15 mm OCT volume scan was acquired from each eye at each visit. A total of 286 and 284 unique visit pairs were thus available where OCT scans were obtained 12 months and ≤1 month apart respectively, serving as the case and control groups respectively. Widefield OCT scans from these visit pairs were evaluated by two graders, who assessed the ganglion cell complex (GCC) thickness and thickness difference maps for glaucoma progression, masked to the time difference between the two scans.

Main outcome measures: Percentage of eyes deemed as progressing at 95% specificity.

Results: Evaluation of widefield OCT scans identified >2 times as many eyes as progressing over a 12-month period (Grader 1 = 36.7%, Grader 2 = 38.1%) than cpRNFLT measurements from spectral-domain OCT (16.8%; P<0.001 for both) at 95% specificity. For the subset of 96 (62%) eyes with a baseline visual field mean deviation (MD) ≥-6 dB, evaluation of widefield OCT scans identified ≥3 times as many eyes as progressing (Grader 1= 41.1, Grader 2 = 46.3%) compared to cpRNFLT measurements (13.6%; P<0.001 for both). There was substantial between-grader agreement for the eyes identified as progressing on widefield OCT imaging (Gwet's first-order coefficient [AC₁] = 0.76). Evaluation of widefield OCT scans in a two-arm trial seeking to detect a ≥30% treatment effect in one study eye with 80% power was estimated to reduce sample size requirements by 69% compared to cpRNFLT measurements, or by 80% when only including eyes with an MD ≥-6 dB.

Conclusions: Qualitative evaluation of widefield OCT scans showed an enhanced detection rate for structural progression than cpRNFLT measurements in glaucoma eyes.