Optical Coherence Tomography Angiography Vessel Density in Healthy, Pseudoexfoliation Syndrome and Exfoliative Glaucoma: Diagnostic Accuracy and Relationship with Structural Parameters.

Abstract

Purpose: To evaluate the diagnostic accuracy and relationship between structural and vascular measurements in pseudoexfoliation syndrome (PEX) and pseudoexfoliative glaucoma (GEX).

Methods: Observational, case-control, and monocentric study conducted from March 2022 to April 2023. The study population comprised 153 eyes from 83 individuals divided into three groups: healthy (49), PEX (51), and GEX (53), with healthy subjects randomly selected from a cohort of nonglaucomatous patients. Structural parameters, including ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL) were measured using spectral domain-optical coherence tomography (OCT). Vascular parameters were obtained from papillary and macular scans through OCT-angiography (OCT-A). The papillary whole-image vessel density (pWiVD), circumpapillary vessel density (cpVD), papillary vessel density (pVD), vessel densities in the superior, temporal, inferior, and nasal quadrants, as well as the macular WiVD, and the parafoveal and perifoveal vessel densities were measured. Structural parameters involved mean RNFL, superior, temporal, inferior, and nasal quadrant RNFL thicknesses, mean, inferior, and superior GCC thicknesses.

Results: The analysis of OCT-A parameters revealed a significant decrease in all vascular densities measured in the papillary region between the GEX and PEX groups and between the PEX and control groups, except for the pVD, which was comparable between the latter 2 groups (P = 0.051). At the level of the macular region, we found a significant decrease in the vascular densities of the superficial plexus, more pronounced in the parafoveal region, in the GEX group compared to the PEX group and in the PEX group compared to the control group. No difference was noted in the deep vascular plexus. Strong correlations were noted between cpVD and average RNFL (r = 0.83), superficial parafoveal vessel density and GCC (r = 0.72), and between cpVD and superficial parafoveal vessel density (r = 0.84). Regression analyses showed cpVD (the area under the curve = 0.958) provided the best diagnostic value in distinguishing between PEX and GEX.

Conclusions: cpVD is critical for detecting GEX, indicating that significant loss of peripapillary microvasculature with preserved structure strongly suggests GEX diagnosis.