Effect of Macular Vascular Density on Central Visual Function and Macular Structure in Glaucoma Patients

In patients with glaucomatous parafoveal scotoma, evidence of compromised vascular circulation was commonly seen. The purpose of this study is to evaluate the relationship between macular vascular density (VD) and central visual function and structure in glaucoma patients. We enrolled 46 eyes of normal tension glaucoma (NTG) patients with parafoveal scotoma. All subjects underwent measurement of segmented macular thickness in each layer and optical coherence tomography angiography (OCTA) to assess VD of macula. Correlation coefficients of VD with structural parameters were identified and multivariate regression analyses were performed to verify factors affecting the MD of SITA 10-2. Superficial VD in NFL, GCL and IPL showed significant correlation with thickness of those layers, but deep VD in INL did not show meaningful correlation with any structural parameters. However, deep VD showed significant correlations with central visual field parameters such as MD of SITA 10-2. By multivariate regression analysis, the significant factors affecting central visual function were deep VD. Different multivariate regression models including segmented macular thicknesses were compared and R-2 value was best for the model with deep VD, not containing superficial VD (R-2 = 0.326, p= 0.001). Assigning subjects as worse or better visual functional group using regression line, deep VD of worse functional group was significantly lower than that of better group. In couclusion, decreased deep VD was an independent risk factor for central scotoma in addition to structural thinning. Taking both macular thickness and vascular circulation into acount, the deterioration of central visual function could be predicted more precisely.