Artifact Rates for 2D Retinal Nerve Fiber Layer Thickness Versus 3D Neuroretinal Rim Thickness Using Spectral-Domain Optical Coherence Tomography

Abstract

Purpose To compare the rates of clinically significant artifacts for two-dimensional peripapillary retinal nerve fiber layer (RNFL) thickness versus three-dimensional (3D) neuroretinal rim thickness using spectral-domain optical coherence tomography (SD-OCT). Methods Only one eye per patient was used for analysis of 120 glaucoma patients and 114 normal patients. For RNFL scans and optic nerve scans, 15 artifact types were calculated per B-scan and per eye. Neuroretinal rim tissue was quantified by the minimum distance band (MDB). Global MDB neuroretinal rim thicknesses were calculated before and after manual deletion of B-scans with artifacts and subsequent automated interpolation. A clinically significant artifact was defined as one requiring manual correction or repeat scanning. Results Among glaucomatous eyes, artifact rates per B-scan were significantly more common in RNFL scans (61.7%, 74 of 120) compared to B-scans in neuroretinal rim volume scans (20.9%, 1423 of 6820) (95% confidence interval [CI], 31.6–50.0; P < 0.0001). For clinically significant artifact rates per eye, optic nerve scans had significantly fewer artifacts (15.8% of glaucomatous eyes, 13.2% of normal eyes) compared to RNFL scans (61.7% of glaucomatous eyes, 25.4% of normal eyes) (glaucoma group: 95% CI, 34.1–57.5, P < 0.0001; normal group: 95% CI, 1.3–23.3, P = 0.03). Conclusions Compared to the most commonly used RNFL thickness scans, optic nerve volume scans less frequently require manual correction or repeat scanning to obtain accurate measurements. Translational Relevance This paper illustrates the potential for 3D OCT algorithms to improve in vivo imaging in glaucoma.

Measurement of retinal nerve fiber layer thickness with a deep learning algorithm in ischemic optic neuropathy and optic neuritis

“…Several studies have demonstrated high rates of errors on peripapillary RNFL segmentation in glaucomatous eyes. 4 – 7 , 14 , 15 Mansberger et al 5 have found that automated OCT machine data resulted in a 1.6 μm thinner RNFL thickness than the ground-truth measurements determined by manual refinement. Manual refinement changed 8.5% of scans to a different global glaucoma classification wherein 23.7% of borderline classifications become normal.…”

“…However, the scans can be affected by movement, media opacity, algorithm failure or poor signal to noise ratios and misidentification of the anterior and posterior boundaries of the RNFL and incomplete segmentation are artifacts that are consistently described in glaucoma eyes 4 – 6 . In some studies, the artifact rates of 46.3% and 61.7% for OCT B scans in glaucoma eyes were reported 4 , 7 . Such errors may cause false measurements of the thicknesses of the different layers and structures.…”

Comparison of Retinal Nerve Fiber Layer Thickness Between Mild to Moderately Myopic Eyes with Normal Eyes

“…It was found that the myopic changes were more substantial (p = 0.001) than the hypermetropia (p = 0.031). Ganglion cell thickness (GCL) studies have shown a greater GCL thinning in people with high myopia than in people with moderate and low myopia [23][24] .…”

New views on three-dimensional imaging technologies for glaucoma: an overview

“…An advantage of high-density MDB rim measurements in 3D space is that more data is obtained, resulting in fewer unusable scans. Park et al [ 36 ▪▪ ] showed that the 3D MDB thickness parameter has only 15.8% unusable scans, compared with 2D RNFL thickness with 61.7% unusable scans.…”