Automated Spectral-Domain vs Swept-Source OCT Angiography in Relation to Glaucoma Severity

Précis: Higher radial peripapillary capillary density on OCT-A correlates independently with better visual field metrics in primary open-angle glaucoma, with similar diagnostic performance across robotic spectral-domain and swept-source OCT platforms. Purpose: To investigate the association between optical coherence tomography angiography (OCT-A) metrics and visual field (VF) mean deviation (MD) using a robotic spectral-domain OCT (SD-OCT) and a swept-source OCT (SS-OCT). Methods: In this prospective cross-sectional study, participants with primary open-angle glaucoma (POAG) underwent OCT-A imaging with both Topcon Maestro2 (SD-OCT) and Topcon Triton (SS-OCT). Radial peripapillary capillary (RPC) density of the superficial vascular plexus (SVP) was derived from 6×6 mm² scans centered on the optic nerve head (ONH). Associations between OCT-A metrics and VF parameters—including mean deviation (MD), visual field index (VFI), and pattern standard deviation (PSD)—were assessed using linear mixed-effects models, adjusting for scan quality, age, and retinal layer thickness. Results: A total of 28 eyes from 18 patients met study criteria. In a multivariable model, each+1% in RPC density was associated with: a higher+1.09 dB MD on the SD-OCT ( P= 0.0241) and+1.75 dB on the SS-OCT ( P= 0.0028); a higher VFI of+3.50% ( P= 0.0181) for SD-OCT and+5.13% ( P= 0.0019) for SS-OCT; a lower PSD of –0.92 dB ( P= 0.0029) with SD-OCT and –1.21 dB ( P= 0.0002) with SS-OCT. Conclusions: OCT-A–derived RPC density is an independent correlate of VF MD across both SD- and SS-OCT platforms. Despite differences in hardware and acquisition methods, both systems demonstrated comparable diagnostic performance. These findings support the integration of OCT-A into glaucoma assessment and highlight the utility of automated SD-OCT platforms in both clinical and screening environments.