Comparison of Superficial versus Deep Macula Vessel Density Measurements in Normal, Glaucoma Suspect, and Glaucoma Eyes

Abstract

Purpose : Recent advances in optical coherence tomography angiography (OCT-A) have allowed for the quantitative and qualitative assessment of the microvasculature of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) of the retina and optic nerve head. Most glaucoma studies characterizing macula microvasculture have focused on SCP vessel density (SCP VD) measurements, in part because DCP VD measurements have artifacts that lead to projection of superficial vessels to the deeper layers. The purpose of this study was to characterize SCP and projection-resolved DCP VD measurements of macula OCT-A scans in normal, glaucoma suspect and glaucoma eyes.

Methods : This cross-sectional study included 346 eyes of 206 participants (49 eyes from 26 age-matched healthy subjects, 71 eyes from 38 glaucoma suspects, and 226 eyes from 142 glaucoma patients) from the Diagnostics Innovations in Glaucoma Study (DIGS) with good quality Optovue AngioVue macula images. Whole-image VD (wiVD) measurements in the SCP and automated projection resolved DCP were compared among groups using linear mixed model analysis, and diagnostic accuracies were compared using area under the receiver operating characteristic curve (AUC).

Results : The mean wiVD in the SCP and DCP layers was highest in healthy eyes (47.0%, 49.0%, respectively), followed by glaucoma suspects (45.7%, 48.6%), and glaucoma patients (43.1%, 48.7%), No significant difference between healthy and glaucoma suspect SCP VD measurements were found (p = 0.112), but significant differences were found between healthy and glaucoma patients (p < 0.001), and between glaucoma patients and glaucoma suspects (p < 0.001). DCP VD measurements were not significantly different among diagnostic groups (p > 0.050). AUC was generally higher for SCP AUC wiVD than DCP wiVD AUC measurements, which were generally close to chance (AUC ~0.50). Specifically, SCP wiVD (AUC = 0.63) had a larger AUC for distinguishing glaucoma suspect eyes from glaucoma eyes when compared to DCP wiVD (AUC = 0.48) (p = 0.004). SCP wiVD (AUC = 0.73) also showed greater AUC for differentiating between healthy and glaucoma eyes when compared to DCP wiVD (AUC = 0.51) (p < 0.001).

Conclusions : Macula SCP vessel density measurements show better diagnostic accuracy than DCP vessel density measurements for detection of glaucoma.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.