Glaucoma Diagnosis Using Multivariate Analysis of Optical Coherence Tomography Angiography Compared to Clinical and Structural Retinal Data

Purpose: To characterize the ability of ImageJ-derived measurements of Optical Coherence Tomography Angiography (OCTA) to diagnose healthy vs Primary Open-Angle Glaucoma (POAG) Eyes. Methods: This retrospective study analyzed 85 healthy and 81 POAG eyes. Initially, demographics, historical data, intraocular pressure, cup/disc ratio and retinal nerve fiber layer thickness were collected for all patients. Thereafter, quantitative vascular parameters including Vessel Density (VD), Vessel Length Density (VLD) and Fractal Dimension (FD) were obtained by analyzing OCTA scans using the open-source software ImageJ. Measurements were obtained from the Radial Peripapillary Capillary (RPC) layer of the optic nerve head and the superficial and deep capillary plexuses of the macula. Fifty healthy and fifty POAG eyes (training set) were randomly selected to train two diagnostic models: one based on OCTA parameters (model A) and the other based on clinical and structural data (model B). These models were tested on the remaining 35 healthy and 31 POAG eyes and receiver operating curves were constructed to compare their ability to identify POAG. Results: VD, VLD and FD as obtained by ImageJ were all significantly reduced in the POAG group (p < 0.0001). The RPC layer was the most effective at classifying glaucoma (AUC = 0.9184, CI: 0.85-0.98). Model A (AUC = 0.917, CI: 0.847-0.986) slightly outperformed model B (AUC = 0.863, CI: 0.776-0.949), albeit not to the level of statistical significance (p = 0.111) Conclusion: Our pilot study indicates that OCTA vascular parameters are similar in effectiveness to clinical exam and structural features at diagnosing glaucoma. Keywords: Glaucoma; Optic Neuropathy; Optical Coherence Tomography Angiography; Retina; Imagej; Superficial Retinal Capillaries; Deep Retinal Capillaries; Radial Peripapillary Capillaries