Longitudinal OCT Angiography Versus Structural OCT for Predicting Visual Field Progression in Glaucoma

In this longitudinal study, the rate of OCT angiography vessel density loss was an independent predictor of visual field progression in glaucoma, whereas the rate of structural OCT thinning was not.

To compare longitudinal OCT angiography vessel density and structural OCT changes as predictors of visual field (VF) progression in open-angle glaucoma (OAG).

This prospective study included 333 OAG eyes (110 normal-tension) followed quarterly for 4.1±0.9 years and 60 age-matched healthy controls examined at baseline and 6 months. Peripapillary capillary vessel density (pcVD), macular vessel density (mVD), peripapillary retinal nerve fibre layer thickness (pRNFLT) and macular ganglion cell-inner plexiform layer thickness (mGCIPLT) were measured. VF progression was defined by combined event- and trend-based criteria. Linear mixed-effects models compared rates of change; Cox models used cumulatively updated rates as time-dependent predictors.

Controls showed minimal change, with small statistically detectable declines in some parameters. Ninety-eight eyes (29.4%) progressed. Progressors showed faster pcVD (-0.73 vs. -0.56%/year, P=0.022) and parafoveal mVD loss (-1.12 vs. -0.40%/year, P<0.001). In advanced glaucoma, mVD loss remained associated with progression (P<0.001), whereas mGCIPLT (P=0.104) and pRNFLT (P=0.118) changes did not. In multivariable Cox analysis, parafoveal mVD rate (HR 2.15 per 1%/year faster loss, 95% CI 1.52-3.04) and pcVD rate (HR 1.82, 95% CI 1.34-2.47) were independent predictors (both P<0.001), whereas pRNFLT (HR 1.28 per 1 μm/y, P=0.158) and mGCIPLT (HR 1.41, P=0.071) were not.

Vessel density loss independently predicted VF progression, whereas structural OCT thinning was not; in advanced glaucoma, vessel density loss remained associated with progression in mixed-model analyses. Formal head-to-head comparisons were not performed.