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

Abstract

PURPOSE To study the relationship between horizontal central retinal vessel trunk location (CRVTL) on glaucomatous optic discs and sector-specific visual field (VF) loss. DESIGN Retrospective cross-sectional study. METHODS 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. RESULTS 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. CONCLUSIONS 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.

Nasalization of Central Retinal Vessel Trunk Predicts Rapid Progression of Central Visual Field in Open-Angle Glaucoma

“…These findings may be in agreement with previous reports, which showed that the magnitude of association between CRVT nasalization and CVF depression at presentation was significant but small in mild glaucoma (MD ≥ −6 dB). However, the association was more than three-fold in moderate glaucoma (−12 dB ≤ MD < −6 dB) and almost six-fold in severe glaucoma (MD < −12 dB) compared with that in mild glaucoma 14 . www.nature.com/scientificreports www.nature.com/scientificreports/ In our study, CVF progression rates were significantly more rapid in the HNL eyes than those in the LNL eyes based on both 10-24° and GHT maps (P < 0.001, Table 1).…”

“…Previous cross-sectional studies have reported that nasalized CRVT is consistently associated with CVF defects in glaucomatous eyes regardless of disease severity 13,14 . The proposed explanations for this finding include both mechanical and vascular theories.…”

“…Therefore, a nasalized CRVT may result in less mechanical support for the LC in the temporal region, which corresponds to CVF area. A nasalized CRVT may also compromise the adequacy of vascular supply in the temporal region, leading to thinning of the RNFL in the macular region and CVF loss 14 . Furthermore, the correlation between CRVT location and CVF loss was significantly stronger in moderate to severe glaucoma than that in mild glaucoma, suggesting that CRVT nasalization is not the result of glaucoma progression, but rather a stable anatomic parameter that may be a risk factor for development of CVF loss in patients with glaucoma 14 .…”

“…A nasalized CRVT may also compromise the adequacy of vascular supply in the temporal region, leading to thinning of the RNFL in the macular region and CVF loss 14 . Furthermore, the correlation between CRVT location and CVF loss was significantly stronger in moderate to severe glaucoma than that in mild glaucoma, suggesting that CRVT nasalization is not the result of glaucoma progression, but rather a stable anatomic parameter that may be a risk factor for development of CVF loss in patients with glaucoma 14 . Our findings are consistent with the speculation that there is no significant difference in the amount of CRVT NI between baseline and last follow-up measurements in both LNL and HNL groups (Table 1).…”

“…We classified our OAG eyes into two groups (LNL vs. HNL) and measured NI based on the location of CRVT on NA. Although there is currently no universally accepted method to classify CRVT location or quantify CRVT nasalization, the method used in the current study has been validated previously [13][14][15] and may minimize the subjectivity associated with manual localization or measurement of the CRVT location in the ONH. Our subjects were highly selected groups (HNL vs. LNL) of patients based on the location of the CRVT in the ONH according to the method described by Lee et al 15 .…”