TY - JOUR
T1 - Directional optical coherence tomography reveals reliable outer nuclear layer measurements
AU - Tong, Kevin K.
AU - Lujan, Brandon J.
AU - Zhou, Yixiu
AU - Lin, Meng C.
N1 - Publisher Copyright:
Copyright © 2016 American Academy of Optometry.
PY - 2016/6/21
Y1 - 2016/6/21
N2 - Purpose. Directional Optical Coherence Tomography (D-OCT) is a method used to optically segment and identify the outer nuclear layer (ONL) in vivo. The purpose of this study was to determine the repeatability and reproducibility of D-OCT ONL thickness measurements in healthy eyes. Methods. Sixteen healthy eyes of sixteen subjects were imaged using the Cirrus SD-OCT. The OCT beamentry position was varied horizontally and vertically through the pupil, and cross-sectional images were obtained at baseline and 1-month follow-up by two observers. Detailed segmentation was performed to quantify the thickness of ONL without the inclusion of overlying Henle Fiber Layer. Inter-observer, intra-observer, and inter-visit variability was evaluated using Bland- Altman and coefficient of variation analysis for each category. Results. All 16 eyes were successfully imaged, registered, and segmented. The maximum mean (SD) inter-operator difference was 2.6 (4.8) μm. The maximum mean (SD) intra-operator difference was 2.4 (5.3) μm. There was no statistically significant difference in ONL measurements detected between baseline and follow-up (p > 0.05). The mean (SD) differences measured across visits by one operator varied from -1.6 (3.1) to 1.1 (6.1) μm. The mean (SD) coefficient of variance (CV%) for all sectors with horizontal orientation was 9.1% (2.3%), 10.1% (2.5%), and 8.6% (2.3%) for inter-observer, intraobserver, and inter-visit, respectively. The mean (SD) coefficient of variance (CV%) for all sectors with vertical orientation was 8.3% (1.8%), 6.9% (1.4%), and 8.3% (2.1%) for inter-observer, intra-observer, and inter-visit, respectively. The majority of the variation of paired repeated measurements originated from between-subject variance. The within-subject variance accounted for less than 1% of the total variability. Conclusions. ONL thickness measurements can be quantified with good repeatability and reproducibility using D-OCT. Identifying the magnitude of D-OCT variability among normal subjects will allow for improved development of future clinical studies that quantitatively track the progression of macular pathology.
AB - Purpose. Directional Optical Coherence Tomography (D-OCT) is a method used to optically segment and identify the outer nuclear layer (ONL) in vivo. The purpose of this study was to determine the repeatability and reproducibility of D-OCT ONL thickness measurements in healthy eyes. Methods. Sixteen healthy eyes of sixteen subjects were imaged using the Cirrus SD-OCT. The OCT beamentry position was varied horizontally and vertically through the pupil, and cross-sectional images were obtained at baseline and 1-month follow-up by two observers. Detailed segmentation was performed to quantify the thickness of ONL without the inclusion of overlying Henle Fiber Layer. Inter-observer, intra-observer, and inter-visit variability was evaluated using Bland- Altman and coefficient of variation analysis for each category. Results. All 16 eyes were successfully imaged, registered, and segmented. The maximum mean (SD) inter-operator difference was 2.6 (4.8) μm. The maximum mean (SD) intra-operator difference was 2.4 (5.3) μm. There was no statistically significant difference in ONL measurements detected between baseline and follow-up (p > 0.05). The mean (SD) differences measured across visits by one operator varied from -1.6 (3.1) to 1.1 (6.1) μm. The mean (SD) coefficient of variance (CV%) for all sectors with horizontal orientation was 9.1% (2.3%), 10.1% (2.5%), and 8.6% (2.3%) for inter-observer, intraobserver, and inter-visit, respectively. The mean (SD) coefficient of variance (CV%) for all sectors with vertical orientation was 8.3% (1.8%), 6.9% (1.4%), and 8.3% (2.1%) for inter-observer, intra-observer, and inter-visit, respectively. The majority of the variation of paired repeated measurements originated from between-subject variance. The within-subject variance accounted for less than 1% of the total variability. Conclusions. ONL thickness measurements can be quantified with good repeatability and reproducibility using D-OCT. Identifying the magnitude of D-OCT variability among normal subjects will allow for improved development of future clinical studies that quantitatively track the progression of macular pathology.
KW - Directional OCT
KW - Henle fiber layer
KW - Ocular coherence tomography
KW - Outer nuclear layer
KW - Repeatability
KW - Reproducibility
KW - Retina
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U2 - 10.1097/OPX.0000000000000861
DO - 10.1097/OPX.0000000000000861
M3 - Article
C2 - 27046093
AN - SCOPUS:84979463108
VL - 93
SP - 714
EP - 719
JO - American Journal of Optometry and Physiological Optics
JF - American Journal of Optometry and Physiological Optics
SN - 1040-5488
IS - 7
ER -