OBJECTIVE: To study the effect of optical coherence tomography (OCT) scan circle displacement on retinal nerve fibre layer (RNFL) measurement errors using cubic spline models. METHODS: Forty-nine normal subjects were included in the analysis. In one randomly selected eye in each subject, RNFL thickness around the optic disc was measured by taking 16 circular scans of different sizes (scan radius ranged from 1 to 2.5 mm). The RNFL profile in each eye was constructed with a mathematical model using a smoothing spline approximation. Scan circle (diameter 3.4 mm) RNFL measurements (total average, superior, nasal, inferior, and temporal RNFL thicknesses) obtained from eight directions (superior, superonasal, nasal, inferonasal, inferior, inferotemporal, temporal, and superotemporal) displaced at different distances (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 mm) from the disc centre were then computed by a computer program and compared to the 'reference standard' where the scan circle is centred at the optic disc. RNFL measurement error was calculated as the absolute of (RNFL thickness(displaced) - RNFL thickness(reference standard)). RESULTS: The respective mean average, superior, nasal, inferior, and temporal RNFL measurement errors were 2.3+/-2.0, 4.9+/-4.5, 4.1+/-3.8, 6.2+/-7.6, and 3.8+/-3.5 microm upon 0.1 mm scan circle displacement, and 12.1+/-11.4, 27.8+/-18.4, 21.7+/-18.6, 34.8+/-22.9, and 15.2+/-10.7 microm upon 0.7 mm scan circle displacement. Significant differences of average and quadrant RNFL thicknesses were evident between centred and displaced scan circle measurements (all with P<0.001). RNFL measurement error increased in a monotonic fashion with increasing distance away from the disc and the change was direction-dependent. CONCLUSIONS: RNFL measurement error varies with the direction and distance of scan displacement. The superior and the inferior RNFL measurements are most vulnerable to scan displacement errors, whereas the average RNFL thickness is the least susceptible. Obtaining a well-centred scan is essential for reliable RNFL measurement in OCT.
OBJECTIVE: To study the effect of optical coherence tomography (OCT) scan circle displacement on retinal nerve fibre layer (RNFL) measurement errors using cubic spline models. METHODS: Forty-nine normal subjects were included in the analysis. In one randomly selected eye in each subject, RNFL thickness around the optic disc was measured by taking 16 circular scans of different sizes (scan radius ranged from 1 to 2.5 mm). The RNFL profile in each eye was constructed with a mathematical model using a smoothing spline approximation. Scan circle (diameter 3.4 mm) RNFL measurements (total average, superior, nasal, inferior, and temporal RNFL thicknesses) obtained from eight directions (superior, superonasal, nasal, inferonasal, inferior, inferotemporal, temporal, and superotemporal) displaced at different distances (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 mm) from the disc centre were then computed by a computer program and compared to the 'reference standard' where the scan circle is centred at the optic disc. RNFL measurement error was calculated as the absolute of (RNFL thickness(displaced) - RNFL thickness(reference standard)). RESULTS: The respective mean average, superior, nasal, inferior, and temporal RNFL measurement errors were 2.3+/-2.0, 4.9+/-4.5, 4.1+/-3.8, 6.2+/-7.6, and 3.8+/-3.5 microm upon 0.1 mm scan circle displacement, and 12.1+/-11.4, 27.8+/-18.4, 21.7+/-18.6, 34.8+/-22.9, and 15.2+/-10.7 microm upon 0.7 mm scan circle displacement. Significant differences of average and quadrant RNFL thicknesses were evident between centred and displaced scan circle measurements (all with P<0.001). RNFL measurement error increased in a monotonic fashion with increasing distance away from the disc and the change was direction-dependent. CONCLUSIONS: RNFL measurement error varies with the direction and distance of scan displacement. The superior and the inferior RNFL measurements are most vulnerable to scan displacement errors, whereas the average RNFL thickness is the least susceptible. Obtaining a well-centred scan is essential for reliable RNFL measurement in OCT.
Authors: Kyungmoo Lee; Milan Sonka; Young H Kwon; Mona K Garvin; Michael D Abràmoff Journal: Invest Ophthalmol Vis Sci Date: 2013-07-18 Impact factor: 4.799
Authors: Jong S Kim; Hiroshi Ishikawa; Michelle L Gabriele; Gadi Wollstein; Richard A Bilonick; Larry Kagemann; James G Fujimoto; Joel S Schuman Journal: Invest Ophthalmol Vis Sci Date: 2009-09-08 Impact factor: 4.799
Authors: Ziad Khoueir; Firas Jassim; Linda Yi-Chieh Poon; Edem Tsikata; Geulah S Ben-David; Yingna Liu; Eric Shieh; Ramon Lee; Rong Guo; Georgia Papadogeorgou; Boy Braaf; Huseyin Simavli; Christian Que; Benjamin J Vakoc; Brett E Bouma; Johannes F de Boer; Teresa C Chen Journal: Am J Ophthalmol Date: 2017-08-12 Impact factor: 5.258
Authors: Yingna Liu; Huseyin Simavli; Christian John Que; Jennifer L Rizzo; Edem Tsikata; Rie Maurer; Teresa C Chen Journal: Am J Ophthalmol Date: 2014-12-12 Impact factor: 5.258
Authors: Joong Won Shin; Yong Un Shin; Ki Bang Uhm; Kyung Rim Sung; Min Ho Kang; Hee Yoon Cho; Mincheol Seong Journal: PLoS One Date: 2016-10-26 Impact factor: 3.240
Authors: Melvi D Eguia; Emmanouil Tsamis; Zane Z Zemborain; Ashley Sun; Joseph Percival; C Gustavo De Moraes; Robert Ritch; Donald C Hood Journal: Transl Vis Sci Technol Date: 2020-10-19 Impact factor: 3.283