Title : Diagnostic ability of optical coherence tomography angiography vessel density parameters in primary open-angle glaucoma cases
Abstract:
Purpose: To evaluate the findings of optical coherence tomography angiography (OCTA) vessel density parameters in patients with primary open-angle glaucoma (POAG) and investigate both diagnostic performance of OCTA and correlations between control group and patients at different stages of glaucoma.
Methods: This cross-sectional study included POAG patients and healthy volunteers as a control group. All subjects underwent a complete ophthalmological examination and computerized perimetry (GP, [Octopus 900]). Structural characteristics in the macular and peripapillary regions were evaluated using OCT (Cirrus HD-OCT 5000), and vascular parameters were assessed with OCTA (Optovue, RTVue XR100-2) with split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. Additionally, the relationship between glaucoma stage and OCTA findings was analyzed in patients classified based on the global perimetry mean deviation value.
Results: The mean age of the POAG group (27 patients, 51 eyes) was 54.5±11.9 years, while it was 45.1±9.7 years in the control group (54 patients, 54 eyes) (p=0.008). There were no significant differences between the two groups in terms of other demographic characteristics (all p>0.05). Twenty-four eyes (47%) were classified as early-stage, 12 eyes (23.5%) as moderate-stage, and 15 eyes (29.5%) as advanced-stage glaucoma. OCTA radial peripapillary capillary (RPC) vessel density (VD) analyses revealed that peripapillary VD (ppVD) area’s under the receiver operating characteristic curve (AUC) of the inferior Hemi [AUC: 0.796(0.665-0.927)] and average ppVD [AUC: 0.790(0.658-0.921)] parameters had the best AUCs for the detection of early glaucoma. The parameter with the lowest diagnostic performance was the fovea. The correlation analysis revealed that OCTA RPC and EM vessel density parameters were significantly correlated with VF indices MD, RNFL and GCC in different stages of glaucomatous eyes. Average ppVD- RNFL correlation was the best AUC [AUC: 0.833(p<0.001)]. Additionally, when glaucoma patients were analyzed together, SMV density measurements showed that vessel density parameters were lower in advanced-stage POAG eyes compared to early-stage eyes (all p<0.05).
Conclusion: OCTA revealed vascular damage in the macular and peripapillary regions of POAG patients. Radial peripapillary capillary vessel density proved useful for detecting early-stage glaucoma, while more significant vascular damage was observed in the macular region as glaucoma progressed to advanced stages.
Keywords: Macular and peripapillary vessel density, optical coherence tomography angiography, primary open-angle glaucoma
