Longitudinal Structure–Function Relationship between Macular Vessel Density and Thickness and Central Visual Field in Early Glaucoma

Abstract

To investigate the relationship of longitudinal changes in macular vessel density (VD) from OCT angiography and in ganglion cell complex (GCC) from OCT with central visual field (VF) in eyes with early glaucoma. Observational cohort. A total of 95 eyes, 37 preperimetric and 58 with early glaucoma (24-2 VF mean deviation [MD] ≥-6 decibels), with an average follow-up of 3.8 years and 5.3 visits, were included. Whole-image VD (wiVD) and whole-image GCC (wiGCC) and parafoveal scans, as well as localized regions of interest (LROIs), hemiretinae of whole images, and superior, inferior, temporal, and nasal sectors of parafoveal maps, were matched with central VF locations. Age-adjusted rates of change of VD, GCC, mean sensitivity of VF locations, and 10-2 VF MD were calculated using linear mixed-effect models. Normalized rates of change were calculated for comparison of change rates in wiVD and wiGCC. Structure-function (SF) correlations of VD and GCC with central VF measurement change rates and comparison of different correlations of SF relationships after bootstrapping the difference of the correlation coefficients. Vessel density loss and GCC thinning demonstrated significant correlations with central VF damage, globally and with most LROIs. The SF correlation (r, 95% confidence interval [CI]) between wiVD and 10-2 VF MD change rates was 0.42 [0.24, 0.58], whereas it was 0.27 [0.08, 0.45] between wiGCC and 10-2 VF MD changes rates (all P < 0.05). In contrast to GCC thinning, VD loss in the parafoveal sectors demonstrated significant correlations with central VF damage in inferior and temporal sectors. Differences in the relationship of SF with central VF damage were not significant between VD loss and GCC thinning. The mean (95% CI) normalized change rates of wiVD (-7.40 [-7.71 to 7.09] %/year) was faster than that of wiGCC (-2.39 [-2.94 to 1.84] %/year) (P < 0.05). Rates of VD loss and GCC thinning are associated with central VF loss over time. Assessment of both macular VD and GCC thickness should be considered for evaluation of glaucoma progression.