Purpose To determine the diagnostic capability of peripapillary 3-dimensional (3D) retinal nerve fiber layer (RNFL) volume measurements from spectral domain optical coherence tomography (OCT) volume scans for open angle glaucoma (OAG). Design Assessment of diagnostic accuracy. Methods Setting Academic clinical setting. Study population 180 patients (113 OAG and 67 normal subjects). Observation procedures One eye per subject was included. Peripapillary 3D RNFL volumes were calculated for global, quadrant, and sector regions, using four different sized annuli. Peripapillary 2D RNFL thickness circle scans were also obtained. Main outcome measures Area under the receiver operating characteristic curve (AUROC) values, sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios. Results Among all 2D and 3D RNFL parameters, best diagnostic capability was associated with inferior quadrant 3D RNFL volume of the smallest annulus (AUROC curve value 0.977). Otherwise, global 3D RNFL volume AUROC curve values were comparable to global 2D RNFL thickness AUROC curve values for all 4 annuli sizes (p values: 0.0593 to 0.6866). When comparing the 4 annuli sizes for global RNFL volume, the smallest annulus had the best AUROC curve values (p values: 0.0317 to 0.0380). The smallest sized annulus may have the best diagnostic potential partly due to having no areas excluded for being larger than the 6×6 mm square scanned region. Conclusion Peripapillary 3D RNFL volume showed excellent diagnostic performance for detecting glaucoma. Peripapillary 3D RNFL volume parameters have the same or better diagnostic capability compared to peripapillary 2D RNFL thickness measurements, although differences were not statistically significant.

Purpose: To compare artifact rates in two-dimensional (2D) versus three-dimensional (3D) retinal nerve fiber layer (RNFL) scans using Spectralis optical coherence tomography (OCT) Methods: Thirteen artifact types in 2D and 3D RNFL scans were identified in 106 glaucomatous eyes and 95 normal eyes. Artifact rates were calculated per B-scan and per eye. In 3D volume scans, artifacts were counted only for the 97 B-scans used to calculate RNFL parameters for the 2.5-3.5-mm annulus. 3D RNFL measurements were calculated twice, once before and again after deletion of B-scans with artifacts and subsequent automated interpolation.Results: For 2D scans, artifacts were present in 58.5% of B-scans (62 of 106) in glaucomatous eyes. For 3D scans, a mean of 35.4% of B-scans (34.3 of 97 B-scans per volume scan) contained an artifact in 106 glaucomatous eyes. For 3D data of glaucoma patients, mean global RNFL thickness values were similar before and after interpolation (77.0 ± 11.6 μm vs. 75.1 ± 11.2 μm, respectively; P = 0.23). Fewer clinically significant artifacts were noted in 3D RNFL scans, where only 7.5% of glaucomatous eyes (8 of 106) and 0% of normal eyes (0 of 95) had artifacts, compared to 2D RNFL scans, where 58.5% of glaucomatous eyes (62 of 106) and 14.7% of normal eyes (14 of 95) had artifacts. Conclusions:Compared to 2D RNFL scans, 3D RNFL volume scans less often require manual correction to obtain accurate measurements.Translational Relevance: 3D RNFL volume scans have fewer clinically significant artifacts compared to 2D RNFL thickness scans.

PurposeTo compare the diagnostic capability of three-dimensional (3D) macular parameters against traditional two-dimensional (2D) retinal nerve fiber layer (RNFL) thickness using spectral domain optical coherence tomography. To determine if manual correction and interpolation of B-scans improve the ability of 3D macular parameters to diagnose glaucoma.MethodsA total of 101 open angle glaucoma patients (29 with early glaucoma) and 57 healthy subjects had peripapillary 2D RNFL thickness and 3D macular volume scans. Four parameters were calculated for six different-sized annuli: total macular thickness (M-thickness), total macular volume (M-volume), ganglion cell complex (GCC) thickness, and GCC volume of the innermost 3 macular layers (retinal nerve fiber layer + ganglion cell layer + inner plexiform layer). All macular parameters were calculated with and without correction and interpolation of frames with artifacts. The areas under the receiver operating characteristic curves (AUROC) were calculated for all the parameters.ResultsThe 3D macular parameter with the best diagnostic performance was GCC-volume-34, with an inner diameter of 3 mm and an outer of 4 mm. The AUROC for RNFL thickness and GCC-volume-34 were statistically similar for all regions (global: RNFL thickness 0.956, GCC-volume-34 0.939, P value = 0.3827), except for the temporal GCC-volume-34, which was significantly better than temporal RNFL thickness (P value = 0.0067). Correction of artifacts did not significantly change the AUROC of macular parameters (P values between 0.8452 and 1.0000).ConclusionsThe diagnostic performance of best macular parameters (GCC-volume-34 and GCC-thickness-34) were similar to or better than 2D RNFL thickness. Manual correction of artifacts with data interpolation is unnecessary in the clinical setting.

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Precis: Three-dimensional (3D) spectral domain optical coherence tomography (OCT) volume scans of the optic nerve head (ONH) and the peripapillary area are useful in the management of glaucoma in patients with a type I or II Boston Keratoprosthesis (KPro). Purpose: The purpose of this study was to report the use of spectral domain OCT in the management of glaucoma in patients with a type I or II Boston KPro. Materials and Methods: This study is an observational case series. Four consecutive patients with KPro implants were referred for glaucoma evaluation. A comprehensive eye examination was performed which included disc photography, visual field testing, and high-density spectral domain OCT volume scans of the ONH and the peripapillary area. 2D and 3D parameters were calculated using custom-designed segmentation algorithms developed for glaucoma management. Results: Spectral domain OCT parameters provided useful information in the diagnosis and management of 4 KPro patients. OCT parameters which can be used in KPro patients included 2D retinal nerve fiber layer (RNFL) thickness, 3D peripapillary RNFL volume, 3D peripapillary retinal thickness and volume, 3D cup volume, and 3D neuroretinal rim thickness and volume. In 3 of 4 cases where the traditional 2D RNFL thickness scan was limited by artifacts, 3D spectral domain OCT volume scans provided useful quantitative objective measurements of the ONH and peripapillary region. Therefore, 3D parameters derived from high-density volume scans as well as radial scans of the ONH can be used to overcome the limitations and artifacts associated with 2D RNFL thickness scans. Conclusions: Spectral domain OCT volume scans offer the possibility to enhance the evaluation of KPro patients with glaucoma by using both 2D and 3D diagnostic parameters that are easily obtained in a clinic setting.

Abstract Purpose: To determine if inter-eye asymmetry of a three-dimensional neuroretinal rim parameter, the minimum distance band, is useful in differentiating normal from open-angle glaucoma eyes. Materials and Methods: This is a cross-sectional study. Both eyes of 28 normal subjects 33 glaucoma subjects were analyzed. Subjects underwent spectral domain optical coherence tomography imaging of both eyes. A custom-designed segmentation algorithm calculated mean minimum distance band neuroretinal rim thickness globally, for four quadrants and for four sectors. Inter-eye minimum distance band thickness asymmetry was calculated as the absolute difference in minimum distance band thickness values between the right and left eyes. Results:  Increasing minimum distance band thickness asymmetry was not associated with increasing age or increasing refractive error asymmetry. Glaucoma patients had thinner mean neuroretinal rim thickness values compared to normal patients (209.0 μm versus 306.0 μm, P < 0.001). Glaucoma subjects had greater inter-eye thickness asymmetry compared to normal subjects for the global region (51.9 μm versus 17.6 μm, P < 0.001) as well as for all quadrants and all sectors. For detecting glaucoma, a thickness asymmetry value greater than 28.3 μm in the inferior quadrant yielded the greatest sum of sensitivity (87.9%) and specificity (75.0%). Globally, thickness asymmetry greater than 30.7 μm yielded the greatest sum of sensitivity (66.7%) and specificity (89.3%).  Discussion: This study indicates that inter-eye neuroretinal rim minimum distance band asymmetry measurements, using high-density spectral domain optical coherence tomography volume scans, may be an objective and quantitative tool for the evaluation of open-angle glaucoma patients.

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