Comparison of the Circumpapillary Structure-Function and Vasculature-Function Relationships at Different Glaucoma Stages Using Longitudinal Data

Abstract

Purpose: This study investigated the global and regional correlations between longitudinal structure-function (S-F) and vasculature-function (V-F) data using circumpapillary retinal nerve fiber layer thickness (cpRNFLT) measurements from optical coherence tomography (OCT), circumpapillary vessel density (cpVD) from OCT angiography (OCTA), and the corresponding visual field mean sensitivities at different glaucoma stages.

Methods: A total of 107 eyes from 107 glaucoma patients with progressive visual field (VF) changes followed up for an average of 3.33 ± 1.39 years were enrolled, including early-to-moderate (51 eyes) and advanced (56 eyes) stages. The rates of longitudinal change in the VF mean deviation (MD), cpRNFLT, and cpVD were evaluated using linear mixed-effects models and compared between different glaucoma stages. Longitudinal global and regional S-F and V-F relationships were assessed by repeated measures correlation analysis by glaucoma stage.

Results: No significant differences were found in the rates of VF MD and cpVD changes (P > 0.05) between the two glaucoma stage groups. CpRNFLT decreased more rapidly in the early-to-moderate stage group (P < 0.001) in which significant longitudinal global and regional correlations were found in both S-F and V-F relationships (all P < 0.05), except for the nasal sector. Significant global and regional correlations were only found in V-F relationship in advanced stage cases (all P < 0.05).

Conclusions: Significant longitudinal V-F relationships exist globally and regionally regardless of glaucoma stage but no longitudinal S-F relationship is present in advanced glaucoma. Longitudinal follow-up of cpVD parameters may be useful for monitoring glaucomatous VF progression at all disease stages.

Figure 1.

Circumpapillary regional structure and vasculature function correspondence map in the right eye. (A1) Corresponding SD-OCT cpRNFL thickness sectors with clock-hour division. (A2) Corresponding OCTA cpVD sectors. (A3) VF sectors on the VF pattern deviation map. (B1) OCT and (B2) OCTA en-face images with the cpRNFL and cpVD measurement sectors centered on the optic nerve head. The sectors on OCT and OCTA images that correspond to the regions in the VF map are identically colored.

Figure 2.

Scatterplots and best-fit lines with LOWESS curves showing the relationships between rates of global cpRNFLT thinning/cpVD loss and baseline VF MD. (A) Relationship between rate of global cpRNFLT change and baseline VF MD. (B) Relationship between rate of global cpVD change and baseline VF MD LOWESS curves were appended to each scatterplot in blue, and vertical red lines were represented to highlight the baseline VF MD −15 dB criteria.

Figure 3.

Repeated measures correlation plots representing the longitudinal global and regional correlations between cpRNFL thinning/cpVD loss and the corresponding VFMS loss of each patient in the early-to-moderate glaucoma stage group. (Left figure) Structure-function relationships (cpRNFLT–VFMS). (Right figure) Vasculature-function relationships (cpVD–VFMS). The data from each patient and corresponding regression line are visually distinguished by different colors. Correlation coefficient (r) values are based on repeated measures correlation analyses.

Figure 4.

Repeated-measures correlation plots representing the longitudinal global and regional correlations between cpRNFL thinning/cpVD loss and the corresponding VFMS loss of each patient in the advanced glaucoma stage group. (Left figure) Structure-function relationships (cpRNFLT–VFMS). (Right figure) Vasculature-function relationships (cpVD–VFMS). The data from each patient and corresponding regression line are visually distinguished by different colors. Correlation coefficient (r) values are based on repeated-measures correlation analyses.