Relationship Between Central Retinal Vessel Trunk Location and Visual Field Loss in Glaucoma

Abstract

To study the relationship between horizontal central retinal vessel trunk location (CRVTL) on glaucomatous optic discs and sector-specific visual field (VF) loss. Retrospective cross-sectional study. CRVTL of 421 eyes from 421 patients was manually tracked on the horizontal optic disc axis on fundus images. Focal circumpapillary retinal nerve fiber layer thickness (cpRNFLT) measurements were extracted from optical coherence tomography (OCT). The relationship between focal visual field (VF) loss and CRVTL and focal cpRNFLT was studied by linear regression models. Furthermore, we related central VF loss to CRVTL and focal cpRNFLT separately for mild (VF mean deviation [MD] ≥-6 dB), moderate (-12 dB ≤ MD <-6 dB), and severe (MD <-12 dB) glaucoma. CRVTL nasalization was significantly correlated only to central VF loss (Garway-Heath scheme [central 6 locations, C6]: correlation: r=-0.16, P < .001; macular vulnerability zone [central 2 locations, C2]: r=-0.14, P= .003; central 4 locations [C4]: r=-0.17, P < .001). While focal cpRNFLT at the sectors corresponding to C2 and C6 was significantly correlated to the respective VF sectors as well (C2: r= 0.15, P= .002; C6: r= 0.10, P= .03), multivariate models combining cpRNFLT and CRVTL substantially improved structure-function models compared with cpRNFLT alone (likelihood ratio tests, C2 and C6: P < .001). The correlations between CRVTL and central VF loss of C4 were-0.11 (P= .04),-0.39 (P= .01), and-0.63 (P= .002) for mild, moderate, and severe glaucoma, respectively. CRVTL nasalization is significantly and exclusively correlated to central VF loss for all glaucoma severities independent of cpRNFLT, and thus might be a structural biomarker of central VF loss.