Angular Location of Retinal Nerve Fiber Layer Defect: Association With Myopia and Open-Angle Glaucoma

Abstract

Purpose To compare retinal nerve fiber layer (RNFL) defects’ angle measurements determined from the center of the optic disc and Bruch's membrane opening (BMO), as a function of myopia and open-angle glaucoma (OAG) subtypes. Methods In total, 118 patients with OAG were grouped by axial length (AL; high myopia, AL >26 mm; mild to moderate myopia, 24 ≤ AL ≤26 mm; nonmyopia, AL <24 mm) and OAG subtype (normal-tension glaucoma [NTG], high-tension glaucoma [HTG]). The disc and BMO centers were determined by a merged image of red-free fundus photography and spectral-domain optical coherence tomography. The angular location of the RNFL defect close to the fovea (angle α) was measured from the disc center and BMO center, respectively (angle α disc and angle α BMO ). The difference between angle α disc and α BMO (Δα), as well as the RNFL defect width (angle γ), was evaluated. Results Angle α disc was smaller in myopic eyes and correlated significantly with AL ( P = 0.001), whereas it did not differ among OAG subgroups. Angle α BMO and angle γ were not different in the myopic and OAG subgroups. The Δ α was larger for eyes with higher degree of myopia and had significant correlation with AL ( P < 0.001) and was larger in NTG eyes than in HTG eyes ( P = 0.023). Conclusions The angular location of the RNFL defect measured from the disc center, but not from the BMO center, was closer to the fovea for glaucomatous eyes with higher values of AL. The present study may facilitate understanding of the characteristic locational pattern of the RNFL defect in myopic glaucomatous eyes.

Offset of openings in optic nerve head canal at level of Bruch’s membrane, anterior sclera, and lamina cribrosa

“…Interobserver reproducibility for determination of the centers of the BMO & ASCO, the CRVT location, and the longest meridian of the EOB was evaluated by the pixel values of the x and y coordinates obtained by two independent observers (KML and MK) in 30 randomly selected images from 30 subjects. The standard deviation was calculated, and the coefficient of variation was estimated using, the one-way ANOVA random-effects model 25,26 . The inter-rater reliability of incomplete demarcation of ASCO was assessed by the Cohen's kappa value.…”

Hemisphere opposite to central retinal vascular trunk deviation is earlier affected by glaucomatous damage in primary angle‐closure glaucoma

“…Our strategy for demarcation of the BMO has been described previously (Bak et al, 2020; Choung et al, 2021; Lee et al, 2018c; Lee et al, 2020). The peripapillary area was imaged by SD‐OCT using the EDI technique.…”

“…The CRVT position was determined by the same strategy as employed in our previous studies (Bak et al, 2020; Choung et al, 2021; Lee et al, 2018c; Lee et al, 2020). First, the location of the CRVT was demarcated on both colour‐disc photographs and infrared fundoscopic images.…”

Update on the Utility of Optical Coherence Tomography in the Analysis of the Optic Nerve Head in Highly Myopic Eyes with and without Glaucoma

“…62.8% of subjects with AXL > 26 mm showed at least one false positive red sign on the RNFL thickness map based on non-myopic data [ 82 ].…”