The following is the summary of “Glaucoma Detection in Myopic Eyes: Structural and Vascular Assessment by Optic Coherence Tomography Methods” published in the December 2022 issue of Glaucoma by Cakir, et al.
Although measuring the thickness of the Retinal nerve fiber layer (RNFL) can be useful, the thickness of the neuroretinal rim (NRR) is the most accurate indicator of myopia and glaucomatous damage. The diagnosis of mild to moderate glaucoma in myopia requires more than just a shift in optical coherence tomography angiography (OCT-A) characteristics. The goal of this study is to assess the accuracy of glaucoma diagnosis in myopic individuals using a multimodal evaluation that takes into account RNFL, NRR thickness, and optic nerve head (ONH) OCT-A. Researchers examined the parameters of normal myopic eyes with myopic glaucomatous eyes with an axial length of ≥24 mm. Cirrus 5000 HD-OCT was used to measure the structural features of the ONH and the RNFL thickness at the periphery (Cirrus HD-OCT; Carl Zeiss Meditec, Dublin, CA).
OCT-A imaging was performed using a Cirrus 5000 HD-OCT equipped with AngioPlex. Best cutoff values with the area under curve (AUC) were used to determine the sensitivity and specificity. About 100 normal myopic eyes and 54 eyes affected by myopic glaucoma were tested. Except for the nasal quadrant (P=0.152), myopic glaucoma patients showed thinner RNFL and NRR than healthy myopic persons (P<0.05). Except for the nasal quadrant mean RPC perfusion (P=0.224), all global, regional, and quadrant indices of radial peripapillary capillary (RPC) perfusion and RPC flux index (FI) were significantly lower in the group of myopic glaucoma patients. Myopic people differed significantly (P=0.001) from non-myopic persons in both RNFL and NRR thickness AUCs for glaucoma diagnosis.
On average, the NRR had outstanding diagnostic performance, while the RNFL demonstrated satisfactory performance. Low diagnostic accuracy was seen for RPCs with moderate perfusion and FI. While both average RPC perfusion and average RPC FI AUC were statistically significant (P<0.001), the average NRR AUC was much more so (P<0.001). Investigators conclude that the diagnostic power of NRR thickness was superior to that of RNFL thickness for identifying glaucoma in myopic patients. The perfusion drop in myopic glaucomatous eyes was not adequately discriminative compared with NRR and RNFL thickness measurements, and OCT-A parameters revealed poor diagnostic accuracy for glaucoma.
