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Tetsuro Oshika - One of the best experts on this subject based on the ideXlab platform.
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central corneal thickness measurements using orbscan ii scanning slit topography noncontact specular microscopy and ultrasonic Pachymetry in eyes with keratoconus
Cornea, 2005Co-Authors: Keisuke Kawana, Kazunori Miyata, Tadatoshi Tokunaga, Takahiro Kiuchi, Takahiro Hiraoka, Tetsuro OshikaAbstract:PURPOSE: To compare corneal thickness measurements using Orbscan II scanning slit topography, Topcon SP-2000P noncontact specular microscopy, and ultrasonic Pachymetry in eyes with keratoconus. METHODS: Central corneal thickness was measured in 22 eyes with keratoconus. Eyes with apparent corneal opacity were excluded. Scanning slit topography, noncontact specular microscopy, and ultrasonic Pachymetry were used in this sequence. The acoustic equivalent correlation factor (0.92) was used for Orbscan readings. RESULTS: Three devices gave significantly different corneal thickness readings (P < 0.001, repeated-measure analysis of variance). Measurements with Orbscan scanning slit topography (449.5 +/- 43.2 [SD] mum) were significantly smaller than those of ultrasonic Pachymetry (485.0 +/- 29.3 microm; P < 0.001, Tukey multiple comparison) and SP-2000P noncontact specular microscopy (476.7 +/- 28.3 microm; P = 0.002). There were significant linear correlations between ultrasonic Pachymetry and scanning slit topography (Pearson correlation coefficient r = 0.741, P < 0.001), between scanning slit topography and noncontact specular microscopy (r = 0.880, P < 0.001), and between noncontact specular microscopy and ultrasonic Pachymetry (r = 0.811, P < 0.001). CONCLUSION: In eyes with keratoconus, Orbscan II scanning slit topography system gave significantly smaller corneal thickness readings than the other 2 devices. Measurements taken by noncontact specular microscopy and ultrasonic Pachymetry were comparable. Three devices showed significant linear correlations with one another.
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comparison of corneal thickness measurements using orbscan ii non contact specular microscopy and ultrasonic Pachymetry in eyes after laser in situ keratomileusis
British Journal of Ophthalmology, 2004Co-Authors: Keisuke Kawana, Kazunori Miyata, Tadatoshi Tokunaga, Takahiro Kiuchi, Fumiki Okamoto, Tetsuro OshikaAbstract:Aims: To compare central corneal thickness measurements of three Pachymetry devices in eyes after laser in situ keratomileusis (LASIK). Methods: Central corneal thickness was measured in 203 eyes after myopic LASIK. Orbscan II scanning slit topography (Bausch & Lomb), SP-2000P non-contact specular microscopy (Topcon), and ultrasonic Pachymetry (Tomey) were used in this sequence. Results: Three devices gave significantly different corneal thickness readings (p r = 0.912, p r = 0.968, p r = 0.933, p Conclusion: In post-LASIK eyes, Orbscan II scanning slit topography significantly underestimated corneal thickness. Non-contact specular microscopy gave smaller thickness readings than ultrasonic Pachymetry, but these two units showed an excellent linear correlation.
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corneal thickness measurements scanning slit corneal topography and noncontact specular microscopy versus ultrasonic Pachymetry
Journal of Cataract and Refractive Surgery, 2003Co-Authors: Shigenobu Suzuki, Isao Sakabe, Shiro Amano, Aiko Iwase, Tetsuro Oshika, Makoto AraieAbstract:Abstract Purpose To compare central corneal thickness measurements taken with 3 Pachymetry systems: Orbscan scanning-slit corneal topography/Pachymetry, Topcon SP2000P noncontact specular microscopy, and Tomey ultrasonic Pachymetry. Setting Multicenter study, Tokyo, Japan. Methods In 216 healthy eyes of 114 subjects, scanning-slit topography, noncontact specular microscopy, and ultrasonic Pachymetry were used in that sequence to record central corneal thickness. In another 20 healthy eyes of 13 subjects, 2 sets of measurements were repeated for each Pachymetry to assess repeatability. Results The mean central corneal thickness was compatible between scanning-slit topography (546.9 μm ± 35.4 [SD] ) and ultrasonic Pachymetry (548.1 ± 33.0 μm); however, noncontact specular microscopy gave a significantly smaller mean (525.3 ± 31.4 μm) than the other 2 tests (P Conclusions Corneal thickness readings were comparable between scanning-slit topography and Pachymetry; noncontact specular microscopy gave significantly smaller values. The measurements of the 3 methods showed significant linear correlations with one another. All methods provided acceptable repeatability of measurements.
Kazunori Miyata - One of the best experts on this subject based on the ideXlab platform.
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comparison of central corneal thickness measurements by rotating scheimpflug camera ultrasonic Pachymetry and scanning slit corneal topography
Ophthalmology, 2006Co-Authors: Shiro Amano, Norihiko Honda, Yuki Amano, Satoru Yamagami, Takashi Miyai, Tomokazu Samejima, Miyuki Ogata, Kazunori MiyataAbstract:Purpose To compare central corneal thickness measurements and their reproducibility when taken by a rotating Scheimpflug camera, ultrasonic Pachymetry, and scanning-slit corneal topography/Pachymetry. Design Experimental study. Participants Seventy-four eyes of 64 subjects without ocular abnormalities other than cataract. Methods Corneal thickness measurements were compared among the 3 methods in 54 eyes of 54 subjects. Two sets of measurements were repeated by a single examiner for each Pachymetry in another 10 eyes of 5 subjects, and the intraexaminer repeatability was assessed as the absolute difference of the first and second measurements. Two experienced examiners took one measurement for each Pachymetry in another 10 eyes of 5 subjects, and the interexaminer reproducibility was assessed as the absolute difference of the 2 measurements of the first and second examiners. Main Outcome Measures Central corneal thickness measurements by the 3 methods, absolute difference of the first and second measurements by a single examiner, absolute difference of the 2 measurements by 2 examiners, and relative amount of variation. Results The average measurements of central corneal thickness by a rotating Scheimpflug camera, scanning-slit topography, and ultrasonic Pachymetry were 538±31.3 μm, 541±40.7 μm, and 545±31.3 μm, respectively. There were no statistically significant differences in the measurement results among the 3 methods ( P = 0.569, repeated-measures analysis of variance). There was a significant linear correlation between the rotating Scheimpflug camera and ultrasonic Pachymetry ( r = 0.908, P r = 0.930, P r = 0.887, P Conclusions Mean corneal thicknesses were comparable among rotating Scheimpflug camera, ultrasonic Pachymetry, and scanning-slit topography with the acoustic equivalent correction factor. The measurements of the 3 instruments had significant linear correlations with one another, and all methods had highly satisfactory measurement repeatability.
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central corneal thickness measurements using orbscan ii scanning slit topography noncontact specular microscopy and ultrasonic Pachymetry in eyes with keratoconus
Cornea, 2005Co-Authors: Keisuke Kawana, Kazunori Miyata, Tadatoshi Tokunaga, Takahiro Kiuchi, Takahiro Hiraoka, Tetsuro OshikaAbstract:PURPOSE: To compare corneal thickness measurements using Orbscan II scanning slit topography, Topcon SP-2000P noncontact specular microscopy, and ultrasonic Pachymetry in eyes with keratoconus. METHODS: Central corneal thickness was measured in 22 eyes with keratoconus. Eyes with apparent corneal opacity were excluded. Scanning slit topography, noncontact specular microscopy, and ultrasonic Pachymetry were used in this sequence. The acoustic equivalent correlation factor (0.92) was used for Orbscan readings. RESULTS: Three devices gave significantly different corneal thickness readings (P < 0.001, repeated-measure analysis of variance). Measurements with Orbscan scanning slit topography (449.5 +/- 43.2 [SD] mum) were significantly smaller than those of ultrasonic Pachymetry (485.0 +/- 29.3 microm; P < 0.001, Tukey multiple comparison) and SP-2000P noncontact specular microscopy (476.7 +/- 28.3 microm; P = 0.002). There were significant linear correlations between ultrasonic Pachymetry and scanning slit topography (Pearson correlation coefficient r = 0.741, P < 0.001), between scanning slit topography and noncontact specular microscopy (r = 0.880, P < 0.001), and between noncontact specular microscopy and ultrasonic Pachymetry (r = 0.811, P < 0.001). CONCLUSION: In eyes with keratoconus, Orbscan II scanning slit topography system gave significantly smaller corneal thickness readings than the other 2 devices. Measurements taken by noncontact specular microscopy and ultrasonic Pachymetry were comparable. Three devices showed significant linear correlations with one another.
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comparison of corneal thickness measurements using orbscan ii non contact specular microscopy and ultrasonic Pachymetry in eyes after laser in situ keratomileusis
British Journal of Ophthalmology, 2004Co-Authors: Keisuke Kawana, Kazunori Miyata, Tadatoshi Tokunaga, Takahiro Kiuchi, Fumiki Okamoto, Tetsuro OshikaAbstract:Aims: To compare central corneal thickness measurements of three Pachymetry devices in eyes after laser in situ keratomileusis (LASIK). Methods: Central corneal thickness was measured in 203 eyes after myopic LASIK. Orbscan II scanning slit topography (Bausch & Lomb), SP-2000P non-contact specular microscopy (Topcon), and ultrasonic Pachymetry (Tomey) were used in this sequence. Results: Three devices gave significantly different corneal thickness readings (p r = 0.912, p r = 0.968, p r = 0.933, p Conclusion: In post-LASIK eyes, Orbscan II scanning slit topography significantly underestimated corneal thickness. Non-contact specular microscopy gave smaller thickness readings than ultrasonic Pachymetry, but these two units showed an excellent linear correlation.
Dennis S.c. Lam - One of the best experts on this subject based on the ideXlab platform.
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comparative study of central corneal thickness measurement with slit lamp optical coherence tomography and visante optical coherence tomography
Ophthalmology, 2008Co-Authors: Christopher Kaishu Leung, Lee Wong, Carol Y Cheung, Chi Pui Pang, Robe N Weinreb, Dennis S.c. LamAbstract:Purpose To evaluate the repeatability and reproducibility of central corneal thickness (CCT) measurements obtained by 2 anterior segment optical coherence tomography (OCT) imaging systems and to examine their agreements with ultrasound Pachymetry. Design Observational cross-sectional study. Participants Fifty eyes from 50 healthy normal subjects were recruited. Methods In one randomly selected eye in each subject, CCT was measured by slit-lamp OCT (SLOCT), Visante OCT, and ultrasound Pachymetry. For anterior segment OCT measurements, both automatic and manual CCTs were obtained. Twenty-five of the 50 subjects were invited for 2 more visits within a week to evaluate repeatability and reproducibility of CCT measurement. Main Outcome Measures Central corneal thickness measurement obtained by the 3 methods and their agreements. Intrasession and intersession within-subject standard deviation (S w ), precision (1.96×S w ), coefficient of variation (CV w ) (100×S w /overall mean), and intraclass correlation coefficient (ICC) were calculated to evaluate repeatability and reproducibility. Results Good repeatability and reproducibility were found for both automatic and manual CCT measurements obtained by SLOCT and Visante OCT. For intrasession repeatability, CV w and ICC values ranged between 0.9% and 1.2% and 0.96 and 0.98, respectively. For intersession reproducibility, the respective CV w and ICC values ranged between 1.2% and 1.4% and 0.94 and 0.96. Although no significant difference was found between automatic/manual SLOCT measurements and ultrasound Pachymetry, automatic Visante OCT CCT (535.7±30.2 μm) was significantly less than CCT with ultrasound Pachymetry (550.3±31.14 μm) ( P P Conclusions Both SLOCT and Visante OCT automatic and manual CCT measurements were reliable and showed comparable agreement with ultrasound Pachymetry. Although the 2 anterior segment OCT imaging systems have similar design and working principles, clinicians should be aware of the differences in CCT measurement between the 2 anterior segment OCTs.
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central corneal thickness measurements using orbscan ii visante ultrasound and pentacam Pachymetry after laser in situ keratomileusis for myopia
Journal of Cataract and Refractive Surgery, 2007Co-Authors: Arthur C K Cheng, Srinivas K Rao, Silvania Lau, Christopher Kaishun Leung, Dennis S.c. LamAbstract:Purpose To compare corneal Pachymetry assessment using 4 measurement methods in eyes after laser in situ keratomileusis (LASIK) for myopia. Setting Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Hong Kong SAR. Methods Fifty-two consecutive patients (103 eyes) who had LASIK for the correction of myopia had Orbscan II (Bausch & Lomb), Visante (Carl Zeiss Meditec), Pentacam (Oculus, Inc.), and ultrasound (US) Pachymetry (Sonomed, 200P) 6 months after surgery. Data were analyzed using the paired sample t test, Bland-Altman plots, and linear regression. Results The mean postoperative Pachymetry measured by US, Orbscan (0.89 acoustic factor), Pentacam, and Visante Pachymetry were 438.2 μm ± 41.18 (SD), 435.17 ± 49.63 μm, 430.66 ± 40.23 μm, and 426.56 ± 41.6 μm, respectively. Compared with the US measurement, Pentacam and Visante measurements significantly underestimated corneal thickness by a mean of 7.54 ± 15.06 μm (P Conclusion Pentacam and Visante measurements of corneal thickness 6 months after LASIK were significantly less than those obtained using Orbscan and US Pachymetry, although all 4 measurement methods showed a high correlation with each other.
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Pachymetry assessment with Orbscan II in postoperative patients with myopic LASIK.
Journal of refractive surgery (Thorofare N.J. : 1995), 2006Co-Authors: Arthur C K Cheng, Emily W. H. Tang, Srinivas K Rao, Dennis S.c. LamAbstract:PURPOSE To compare central corneal thickness after LASIK for myopia, using ultrasonic Pachymetry and Orbscan II measurements, and to evaluate changes in these measurements over time. METHODS Central corneal thickness measurements obtained by ultrasonic Pachymetry and Orbscan II (Bausch and Lomb, Rochester, NY) in patients who underwent myopic LASIK between July 2002 and May 2003 were analyzed. The two measurements were assessed preoperatively and postoperatively at 1 day and 1, 3, 6, and 12 months. RESULTS In 237 eyes, using the correction factor 0.93, no significant difference was noted in the preoperative central corneal thickness measured by ultrasonic Pachymetry (561.89 +/- 28.66 microm) and Orbscan Pachymetry (562.28 +/- 28.18 microm) (P =.713). Postoperatively, the difference was statistically significant at day 1 and 1, 3, and 6 months (P < .001), but was not significant at 12 months (P = .130). CONCLUSIONS Orbscan II measurements of central corneal thickness after myopic LASIK are less than those measured by ultrasonic Pachymetry; however, this difference decreases with time and may not be significant after 1 year.
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Correction factor in Orbscan II in the assessment of corneal Pachymetry.
Cornea, 2006Co-Authors: Arthur C K Cheng, Emily W. H. Tang, Shaheeda Mohamed, Dennis S.c. LamAbstract:Purpose: Comparison of corneal Pachymetry assessment with ultrasound and Orbscan II using acoustic factor and subtraction methods. Methods: Ultrasound and Orbscan Pachymetry for all patients with LASIK performed between July 2002 and May 2003 were retrospectively analyzed. Comparison between the 2 preoperative measurements was analyzed. Results: Using a custom acoustic factor of 0.93, there was no significant difference between the overall ultrasound and Orbscan Pachymetry (P = 0.696). However, there was underestimation in thick comeas and overestimation in thin corneas. Using the subtraction method as the correcting technique, the magnitude of over- and underestimation was reduced. Conclusion: The current correction method by means of acoustic factor may result in error in assessing extremes of corneal thickness. Alternative approaches such as the subtraction method can be considered to achieve more accurate results.
Kakarla V. Chalam - One of the best experts on this subject based on the ideXlab platform.
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comparison of central corneal thickness ultrasound Pachymetry versus slit lamp optical coherence tomography specular microscopy and orbscan
Clinical Ophthalmology, 2015Co-Authors: Wassia Khaja, Amy T Kelmenson, Lee R Ferguson, Kumar Sambhav, Sandeep Grover, Kakarla V. ChalamAbstract:Background Central corneal thickness (CCT) can be measured by using contact and non-contact methods. Ultrasound Pachymetry (US Pachymetry) is a contact method for measuring CCT and is perhaps the most commonly used method. However, non-contact methods like scanning slit topography (Orbscan II), slit-lamp optical coherence tomography (SL-OCT), and specular microscopy are also used. Not many studies have correlated the measurement of CCT with all four modalities. The purpose of this study was to compare and correlate the CCT measurements obtained by US Pachymetry with SL-OCT, specular microscopy, and Orbscan.
Jinhai Huang - One of the best experts on this subject based on the ideXlab platform.
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evaluation of central corneal thickness using corneal dynamic scheimpflug analyzer corvis st and comparison with pentacam rotating scheimpflug system and ultrasound Pachymetry in normal eyes
Journal of Ophthalmology, 2015Co-Authors: Weiqi Zhao, Giacomo Savini, Qinmei Wang, Zixu Huang, Fangjun Bao, Jinhai HuangAbstract:Purpose. To assess the repeatability and reproducibility of central corneal thickness (CCT) measurements by corneal dynamic Scheimpflug analyzer Corvis ST in normal eyes and compare the agreement with Pentacam rotating Scheimpflug System and ultrasound Pachymetry. Methods. 84 right eyes underwent Corvis ST measurements performed by two operators. The test-retest repeatability (TRT), within-subject coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were used to evaluate the intraoperator repeatability and interoperator reproducibility. CCT measurements also were obtained from Pentacam and ultrasound Pachymetry by the first operator. The agreement between the three devices was evaluated with 95% limits of agreement (LoA) and Bland-Altman plots. Results. Corvis ST showed high repeatability as indicated by TRT ≤ 13.0 μm, CoV 0.97. The interoperator reproducibility was also excellent. The CoV was 0.97. Corvis ST showed significantly lower values than Pentacam and ultrasound Pachymetry (P < 0.001). The 95% LoA between Corvis ST and Pentacam or ultrasound Pachymetry were -15.8 to 9.5 μm and -27.9 to 12.3 μm, respectively. Conclusions. Corvis ST showed excellent repeatability and interoperator reproducibility of CCT measurements in normal eyes. Corvis ST is interchangeable with Pentacam but not with ultrasound Pachymetry.
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precision of corneal thickness measurements obtained using the scheimpflug placido imaging and agreement with ultrasound Pachymetry
Journal of Ophthalmology, 2015Co-Authors: Jinhai Huang, Giacomo Savini, Qinmei Wang, Chengfang Wang, Rongrong Gao, Yune ZhaoAbstract:Purpose. To assess the reliability and comparability of measuring central corneal thickness (CCT) and thinnest corneal thickness (TCT) using a new Scheimpflug-Placido analyzer (TMS-5, Japan) and ultrasound (US) Pachymetry. Methods. Seventy-six healthy subjects were prospectively measured 3 times by 1 operator using the TMS-5, 3 additional consecutive scans were performed by a second operator, and ultrasound (US) Pachymetry measurements were taken. The test-retest repeatability (TRT), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were calculated to evaluate intraoperator repeatability and interoperator reproducibility. Agreement among the devices was assessed using Bland-Altman plots and 95% limits of agreement (LoA). Results. The intraoperators TRT and CoV were 0.90. The mean CCT and TCT measurements using the TMS-5 were 15.97 μm (95% LoA from −26.42 to −5.52 μm) and 20.32 μm (95% LoA from −30.67 to −9.97 μm) smaller, respectively, than those using US Pachymetry. Conclusions. The TMS-5 shows good repeatability and reproducibility for measuring CCT and TCT in normal subjects but only moderate agreement with US Pachymetry results. Caution is warranted before using these techniques interchangeably.
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evaluation of corneal thickness using a scheimpflug placido disk corneal analyzer and comparison with ultrasound Pachymetry in eyes after laser in situ keratomileusis
Journal of Cataract and Refractive Surgery, 2013Co-Authors: Jinhai Huang, Giacomo Savini, Chao Pan, Jing Wang, Weina Tan, Jia Chen, Qinmei WangAbstract:Purpose To evaluate the repeatability and reproducibility of corneal thickness measurements in post-laser in situ keratomileusis (LASIK) eyes using a rotating Scheimpflug camera combined with a Placido disk corneal topographer (Sirius) and compare the results with those of ultrasound (US) Pachymetry. Setting Eye Hospital of Wenzhou Medical College, Wenzhou, China. Design Comparative evaluation of a diagnostic test or technology. Methods Patients were examined 3 times with the Scheimpflug–Placido topographer by 2 examiners. The central pupil corneal thickness (CT pupil ), apical corneal thickness (CT apex ), and thinnest corneal thickness (CT thinnest ) were recorded. After noncontact examinations, US Pachymetry was used to obtain the central corneal thickness (CCT). Results The Scheimpflug–Placido topographer showed high intraoperator repeatability as indicated by a test–retest repeatability of less than 8.5 μm for CT pupil , CT apex , and CT thinnest , The coefficients of variation (CoV) were less than 0.7%, and the intraclass correlation coefficient was higher than 0.99. Excellent results were also obtained for interoperator reproducibility. All CoVs were less than 0.5%. The 95% limits of agreement between the Scheimpflug–Placido measurement and the US Pachymetry measurements were narrow (−16.62 to 12.44 μm for CT pupil versus US Pachymetry CCT; −17.49 to 12.16 μm for CT apex versus US Pachymetry CCT; −18.59 to 10.90 μm for CT thinnest versus US Pachymetry CCT). Conclusions The Scheimpflug–Placido topographer showed excellent intraoperator repeatability and interoperator reproducibility of CT pupil , CT apex , and CT thinnest measurements in post-LASIK eyes. The CCT measurements obtained using the device were in high agreement with those obtained by US Pachymetry, suggesting that the 2 devices are interchangeable. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.
