Event-Based Progression Detection Among OCT, OCT Angiography, and Visual Field in Glaucoma

Importance: Early detection of glaucoma progression is essential. Optical coherence tomography angiography (OCTA) vascular metrics may identify progression before structural OCT or visual field changes. Objective: To evaluate timing and agreement of event-based progression detection among OCT, OCTA, and visual field testing in glaucoma. Design, Setting, and Participants: This was a retrospective cohort study designed in August 2024. Included were patients from the Diagnostic Innovations in Glaucoma Study (DIGS) who underwent OCT and OCTA imaging and visual field testing from January 2015 to April 2023. Inclusion required 2 or more years of follow-up and 4 or more visits with each modality. Exposures: OCT, OCTA, and visual field testing. Main Outcomes and Measures: OCT and OCTA progression were defined as change exceeding test-retest variability thresholds at 2 consecutive visits; visual field progression was assessed with guided progression analysis. Progression rates and lead times were compared. Results: A total of 180 eyes (111 perimetric, 69 preperimetric) from 116 patients (mean [SD] age, 67.6 [13.7] years; 61 female [52.6%]) were included in this analysis. During mean (SD) follow-up of 5.1 (1.4) years, 107 eyes (59.4%) had progression detected by at least 1 modality as follows: 58 eyes (32.2%) by OCTA vessel density, 45 eyes (25.0%) by OCT circumpapillary retinal nerve fiber layer (CPRNFL) thickness, and 59 eyes (32.8%) by visual field testing. Among eyes with progression, the earliest detection occurred with OCTA vessel density in 40 eyes (37.4%), OCT CPRNFL thickness in 32 eyes (29.9%), and visual field testing in 26 eyes (24.3%). Among 45 stable eyes, specificity was 75.6% for OCT CPRNFL thickness and 68.9% for OCTA vessel density. Mean lead times were 2.3 years for OCTA vessel density before visual field progression (95% CI, 1.3-3.2 years), 1.5 years for OCT CPRNFL thickness before visual field progression (95% CI, 0.6-2.4 years), and 0.2 years for OCT CPRNFL thickness vs OCTA vessel density (95% CI, -0.6 to 0.9 years). Conclusions and Relevance: Results of this cohort study suggest that OCTA vessel density may detect event-based glaucoma progression earlier than OCT or visual field testing at the cost of a slight decrease in specificity compared with OCT. These findings support a potential complementary role for OCTA in glaucoma monitoring, although the cost-benefit of additional testing requires further evaluation.