scholarly journals 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

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ayong Yu ◽  
Weiqi Zhao ◽  
Giacomo Savini ◽  
Zixu Huang ◽  
Fangjun Bao ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Coefficient Of Variation ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Limits Of Agreement ◽  
Corvis St ◽  
Ultrasound Pachymetry ◽  
Repeatability And Reproducibility ◽  
High Repeatability

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 < 0.9%, and ICC > 0.97. The interoperator reproducibility was also excellent. The CoV was <0.9%, and ICC 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.

scholarly journals Precision and Agreement of Central Corneal Thickness Measured with E-pach, A-scan, Corvis ST and Pentacam

2019 ◽  
Author(s):  
Anqi Liu ◽  
Zequan Xu ◽  
Jingjing Wang ◽  
Feng Liu ◽  
Yanming Jiang ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Limits Of Agreement ◽  
Interobserver Reproducibility ◽  
Corvis St ◽  
Test Study ◽  
Repeatability And Reproducibility ◽  
Healthy Eyes

Abstract Purpose To assess the precision (repeatability and reproducibility) and agreement of central corneal thickness (CCT) measurements by E-pach, Pentacam, Corvis ST and A-scan devices in healthy eyes. Methods Instrument diagnostic test study. A total of 100 patients were enrolled to measure right-eye CCT by E-pach, Pentacam, Corvis ST, and A-scan devices. To assess repeatability and reproducibility, the test-retest repeatability (TRT) and intraclass correlation coefficient (ICC) were calculated. The agreement among the four devices was evaluated with Bland-Altman plots. Results The E-pach showed repeatability (ICC=0.9981), interobserver reproducibility (ICC=0.9971) and intersession reproducibility (ICC=0.9825); the Pentacam, Corvis ST and A-scan also showed similar repeatability (all ICC≥0.9679), interobserver reproducibility (all ICC≥0.9730) and intersession reproducibility (all ICC≥0.9647). However, the E-pach yielded CCT values that were obviously lower than those of the A-scan and Pentacam (P<0.001) but higher than those of the Corvis ST (P<0.001). The 95% limits of agreement (LoA) in the Bland-Altman plots were 44.5 µm (E-pach vs. A-scan), 34.9 µm (E-pach vs. Corvis CT) and 32.5 µm (E-pach vs. Pentacam). Conclusions The E-pach is a portable, reliable and inexpensive pachymeter. However, the CCT values obtained from the E-pach are not interchangeable with those from Pentacam, Corvis ST and A-scan devices.

scholarly journals Repeatability and Reproducibility of Measurements Using a NT-530P Noncontact Tono/Pachymeter and Correlation of Central Corneal Thickness with Intraocular Pressure

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Fusako Fujimura ◽  
Kazutaka Kamiya ◽  
Kazuko Fujiwara ◽  
Nobuyuki Shoji ◽  
Kimiya Shimizu
Keyword(s):  
Intraocular Pressure ◽  
Healthy Volunteers ◽  
Coefficient Of Variation ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Limits Of Agreement ◽  
Repeatability And Reproducibility ◽  
Linear Correlations

Purpose. To investigate the repeatability and reproducibility of intraocular pressure (IOP) and central corneal thickness (CCT) measurements using a noncontact tono/pachymeter (NT-530P) and to assess the correlation of CCT with IOP.Methods. Forty-six eyes of healthy volunteers were measured by two examiners. Three consecutive measurements per eye were performed. Repeatability was assessed using the coefficient of variation, and reproducibility was assessed using Bland-Altman plots. Linear correlations were used to determine agreement between CCT and noncorrected IOP and CCT and corrected IOP, which was calculated using a formula built into the NT-530P.Results. The coefficient of variation for IOP was 6.4% and for CCT was 0.4%. The 95% limits of agreement between examiners were−0.17±1.42 mmHg (range:−2.95to 2.61 mmHg) for IOP,−0.93±4.37 μm (range:−9.50to 7.64 μm) for CCT. The corrected IOP was significantly higher than the noncorrected IOP (P=0.010.3). The noncorrected IOP significantly correlated with CCT (r=−0.4883,P=0.0006). The corrected IOP showed no significant correlation with CCT (r=−0.0285,P=0.8509).Conclusions. NT-530P offered repeatability and reproducibility in both IOP and CCT measurements. The corrected IOP calculated using the NT-530P was independent of the CCT, suggesting that this IOP may be less influenced by the central corneal thickness.

scholarly journals Precision of Corneal Thickness Measurements Obtained Using the Scheimpflug-Placido Imaging and Agreement with Ultrasound Pachymetry

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Jinhai Huang ◽  
Giacomo Savini ◽  
Chengfang Wang ◽  
Weicong Lu ◽  
Rongrong Gao ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Normal Subjects ◽  
Limits Of Agreement ◽  
Ultrasound Pachymetry ◽  
Good Repeatability ◽  
Repeatability And Reproducibility ◽  
The Mean ◽  
Thickness Measurements

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 <19 μm and 2.0%, respectively. The interoperators TRT and CoV were <12 μm and 1.0%, respectively, and ICC was >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.

scholarly journals Repeatability and Agreement of Central Corneal Thickness and Keratometry Measurements between Four Different Devices

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Laszlo Kiraly ◽  
Jana Stange ◽  
Kathleen S. Kunert ◽  
Saadettin Sel
Keyword(s):  
Clinical Practice ◽  
Statistical Analysis ◽  
Correlation Coefficient ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Bland Altman Method ◽  
Significant Difference ◽  
Healthy Eyes ◽  
Iolmaster 700

Background.To estimate repeatability and comparability of central corneal thickness (CCT) and keratometry measurements obtained by four different devices in healthy eyes.Methods.Fifty-five healthy eyes from 55 volunteers were enrolled in this study. CCT (IOLMaster 700, Pentacam HR, and Cirrus HD-OCT) and keratometry readings (IOLMaster 700, Pentacam HR, and iDesign) were measured. For statistical analysis, the corneal spherocylinder was converted into power vectors (J0, J45). Repeatability was assessed by intraclass correlation coefficient (ICC). Agreement of measurements between the devices was evaluated by the Bland-Altman method.Results.The analysis of repeatability of CCT data of IOLMaster 700, Pentacam HR, and Cirrus HD-OCT showed high ICCs (range 0.995 to 0.999). The comparison of CCT measurements revealed statistically significant differences between Pentacam HR versus IOLMaster 700 (p<0.0001) and Pentacam HR versus Cirrus HD-OCT (p<0.0001), respectively. There was no difference in CCT measurements between IOLMaster 700 and Cirrus HD-OCT (p=0.519). The repeatability of keratometry readings (J0 and J45) of IOLMaster 700, Pentacam HR, and iDesign was also high with ICCs ranging from 0.974 to 0.999. The Pentacam HR revealed significantly higher J0 in comparison to IOLMaster 700 (p=0.009) and iDesign (p=0.041); however, no significant difference was between IOLMaster 700 and iDesign (p=0.426). Comparison of J45 showed no significant difference between IOLMaster 700, Pentacam HR, and iDesign. These results were in accordance with Bland-Altman plots.Conclusion.In clinical practice, the devices analyzed should not be used interchangeably due to low agreement regarding CCT as well as keratometry readings.

Repeatability and reproducibility of corneal biomechanical parameters derived from Corvis ST

2019 ◽  
Vol 30 (6) ◽  
pp. 1287-1294
Author(s):  
Nermin Serbecic ◽  
Sven Beutelspacher ◽  
Lovro Markovic ◽  
Abhijit Sina Roy ◽  
Rohit Shetty
Keyword(s):  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Coefficient Of Variation ◽  
Intraclass Correlation ◽  
Diurnal Changes ◽  
Good Reliability ◽  
Good Repeatability ◽  
Repeatability And Reproducibility ◽  
Biomechanical Parameters ◽  
High Intraclass Correlation Coefficient

Introduction: The aim of this study was to evaluate repeatability and reproducibility of newly calculated biomechanical parameters of the cornea, developed by our research group. Methods: One eye from each of the 23 healthy subjects was measured three times consecutively, three times at different daytimes and on three different days. The within-subject standard deviation and coefficient of variation, as well as the intraclass correlation coefficient, were calculated for every parameter in each group. Results: Excellent repeatability and reproducibility (coefficient of variation < 5%, intraclass correlation coefficient > 0.75) was found for corrected values measured at A1, HC, and A2 time points (2nd A2 Time, 2nd A1 Time, 2nd HC Time, 2nd HC Def Amp and 2nd A1 Def Amp). Corneal-specific stiffness parameters, which showed good repeatability and reliability, were DA_cor (coefficient of variation = 4.02%, intraclass correlation coefficient = 0.919), KcLinear (coefficient of variation = 4.03%, intraclass correlation coefficient = 0.895), areaForceCornea (coefficient of variation = 3.34%, intraclass correlation coefficient = 0.853) and E2 (coefficient of variation = 4.1%, intraclass correlation coefficient = 0.78). Overall, most parameters fell into the category of good reliability (high intraclass correlation coefficient) and poor reproducibility (low coefficient of variation), including all the parameters describing extraocular deformation (DA_ext, AEPvED, AUC EDef, areaForceExtra, Kg and μg). Comparing the coefficient of variation values for intrasession, intersession and daytime measurements, there were no indices for diurnal changes. Conclusion: Most parameters showed good repeatability and reliability. The extraocular stiffness parameters showed poor reproducibility. KcLinear can serve as a very reliable and repeatable indicator of corneal stiffness.

scholarly journals Reliability of Peak Running Velocity Obtained on the Track Field in Runners of Different Performance Levels

2021 ◽  
Vol 12 ◽  
Author(s):  
Francisco de Assis Manoel ◽  
Cecília Segabinazi Peserico ◽  
Fabiana Andrade Machado
Keyword(s):  
Correlation Coefficient ◽  
Coefficient Of Variation ◽  
High Reliability ◽  
Intraclass Correlation ◽  
Statistical Test ◽  
Limits Of Agreement ◽  
Running Performance ◽  
Performance Levels ◽  
Recreational Runners ◽  
Trained Runners

The aim of this study was to verify the reliability of peak running velocity obtained on the track field (Vpeak_TF) in runners of different performance levels. 39 male endurance runners were divided into two groups: trained runners (TR; n = 22; 10-km time running performance of 35.2 ± 1.7 min), and recreational runners (RR; n = 17; 10-km time running performance of 51.3 ± 4.8 min). They performed three maximal incremental running tests on the official track field (400 m), with an interval of 1 week between trials to determine the reliability of Vpeak_T. The Vpeak_TF showed high reliability, presenting an intraclass correlation coefficient and coefficient of variation of 0.97 and 1.28%, and 0.90 and 1.24% for TR and RR, respectively. Both TR and RR showed lowest bias and limits of agreement between test and retest (Vpeak_TF1 and Vpeak_TF2). In addition, there was no statistical test-retest difference for Vpeak_TF. In addition, the HR and RPE submaximal values were reliable for both TR and RR. Therefore, the Vpeak_TF showed high reliability in both TR and RR. These findings reinforce that the protocol for determining Vpeak_TF, using increments of 1 km h–1 every 3 min is reliable regardless of the performance level of the runners.

scholarly journals Repeatability and reproducibility of Orbscan II

2012 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Raúl Martín ◽  
Maria Izquierdo ◽  
Victoria De Juan ◽  
Guadalupe Rodriguez ◽  
Itziar Fernandez
Keyword(s):  
Corneal Thickness ◽  
Intraclass Correlation ◽  
High Reproducibility ◽  
Non Invasive ◽  
Repeatability And Reproducibility ◽  
Orbscan Ii ◽  
Thickness Measurements ◽  
Best Fit ◽  
High Repeatability ◽  
Healthy Eyes

This study aimed to determine the repeatability and reproducibility of Orbscan for anterior and posterior best fit sphere (BFS), simulated keratometry (Sim-K), and central (CCT) and mid-peripheral (PCT) corneal thickness measurements in healthy eyes. Orbscan was performed in 40 healthy eyes (20 subjects) three consecutive times on each cornea during three visits scheduled over one week. Repeatability and reproducibility coefficients [Bland and Altman&rsquo;s coefficient (BAC), coefficient of variation (CV) and intraclass correlation (ICC)] were calculated for Orbscan anterior and posterior BFS, Sim-K and corneal pachymetry (central, superior, inferior, nasal and temporal locations). Repeatability was calculated using three consecutive measurements during each visit, while reproducibility was calculated using the average of the measurements obtained at each visit. High repeatability was found for all Orbscan measurements (r2&lt;0.01; P&gt;0.05, two-way ANOVA) with BAC and CV &lt;1% (except in PCT coefficients; from 0.97% to 1.67%) and ICC close to 0.98- 0.99 for all visits. High reproducibility was also found for all Orbscan measurements (r2&lt;0.01; P&gt;0.05 two-way ANOVA). BAC values were less than 1% for both BFS and Sim- K, and between 1.21 and 2.20% for corneal pachymetry. CV values were less than 1% (except in superior, nasal and temporal PCT, where they ranged from 1.06 to 1.30%). ICC was close to 0.98-0.99 for all measurements. The BAC of reproducibility was higher than the CV of reproducibility. PCT showed less repeatability and reproducibility than CCT. The Orbscan provides non-invasive, repeatable and reproducible measurements of anterior and posterior BFS, simulated keratometry. and central and mid-peripheral pachymetry in healthy eyes.

scholarly journals Assessment of corneal biomechanics, tonometry and pachymetry with the Corvis ST in myopia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaorui Wang ◽  
Colm McAlinden ◽  
Hongbing Zhang ◽  
Jie Yan ◽  
Dan Wang ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Poor Agreement ◽  
Limits Of Agreement ◽  
Corvis St ◽  
Good Repeatability ◽  
Mean Differences ◽  
Repeatability Limit ◽  
The Right

AbstractTo evaluate the repeatability of Corvis ST corneal biomechanical, tonometry and pachymetry measurements, and agreement of pachymetry measures with the Pentacam HR and RTVue OCT. Three consecutive measurements of the right eye of 238 myopic subjects were acquired with the Corvis ST, Pentacam HR, and RTVue OCT. Repeatability of Corvis ST was evaluated by within-subject standard deviation [Sw] and repeatability limit [r]. The agreement of central corneal thickness (CCT) measurements were compared among the three instruments using the Bland–Altman limits of agreement. Comparisons were further stratified by CCT (Corneathin ≤ 500 µm; Corneanormal = 500–550 µm; Corneathick > 550 µm). Sw was below 1 mmHg in Corneathin, Corneanormal, and Corneathick groups for IOP and bIOP. Sw for SP-A1 were 4.880, 6.128, 7.719 mmHg/mm respectively. Sw for CBI were 0.228, 0.157, 0.076, and correspondingly Sw for TBI and SSI were 0.094 and 0.056, 0.079 and 0.053, 0.070 and 0.053. The Bland–Altman plots for CCT implied poor agreement with mean differences of 29.49 µm between Corvis and OCT, 9.33 µm between Pentacam and OCT, and 20.16 µm between Corvis and Pentacam. The Corvis ST showed good repeatability with the exception of CBI in the various CCT groups. The CCT measured by Corvis ST was not interchangeable with Pentacam HR and RTVue OCT.

scholarly journals Repeatability of automated measurements by a new anterior segment optical coherence tomographer and biometer and agreement with standard devices

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Domenico Schiano-Lomoriello ◽  
Kenneth J. Hoffer ◽  
Irene Abicca ◽  
Giacomo Savini
Keyword(s):  
Intraclass Correlation ◽  
Anterior Segment ◽  
Consecutive Series ◽  
Optical Coherence ◽  
Limits Of Agreement ◽  
Automated Measurements ◽  
Deviation Coefficient ◽  
Corneal Diameter ◽  
High Repeatability ◽  
Good Agreement

AbstractWe assess repeatability of automatic measurements of a new anterior segment optical coherence tomographer and biometer (ANTERION) and their agreement with those provided by an anterior segment-optical coherence tomography device combined with Placido-disk corneal topography (MS-39) and a validated optical biometer (IOLMaster 500). A consecutive series of patients underwent three measurements with ANTERION and one with MS-39. A subgroup of patients underwent biometry also with IOLMaster 500. Repeatability was assessed by means of within-subject standard deviation, coefficient of variation (COV), and intraclass correlation coefficient (ICC). Agreement was investigated with the 95% limits of agreement. Paired t-test and Wilcoxon matched-pairs test were performed to compare the measurements of the different devices. Repeatability of ANTERION measurements was high, with ICC > 0.98 for all parameters except astigmatism (0.963); all parameters apart from those related to astigmatism revealed a COV < 1%. Repeatability of astigmatism improved when only eyes whose keratometric astigmatism was higher than 1.0 D were investigated. Most measurements by ANTERION and MS-39 showed good agreement. No significant differences were found between measurements by ANTERION and IOLMaster, but for corneal diameter. ANTERION revealed high repeatability of automatic measurements and good agreement with both MS-39 and IOLMaster for most parameters.

Detecting subclinical keratoconus by biomechanical analysis in tomographically regular keratoconus fellow eyes

2021 ◽  
pp. 112067212110637
Author(s):  
Victor A Augustin ◽  
Hyeck-Soo Son ◽  
Isabella Baur ◽  
Ling Zhao ◽  
Gerd U Auffarth ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Case Series ◽  
Biomechanical Analysis ◽  
Corvis St ◽  
Corrected Visual Acuity ◽  
The Mean ◽  
Best Corrected Visual Acuity ◽  
Fellow Eyes

Purpose To analyze the tomographically non-affected second eyes of keratoconus patients using the Corvis ST to detect any biomechanical abnormalities or subclinical keratoconus. Methods In this retrospective, single-center, consecutive case series 244 eyes of 122 keratoconus patients were analyzed between November 2020 and February 2021. Fourteen fellow eyes fulfilled the inclusion criteria and showed no clinical or tomographic signs of keratoconus. Main outcome measures included best-corrected visual acuity, tomographic and biomechanical analyses using Scheimpflug imaging: Pentacam and Corvis ST (Oculus, Wetzlar, Germany). Tomographic analyses included anterior and posterior simulated keratometry, K-Max, central corneal thickness, thinnest corneal thickness, Belin/Ambrosio Ectasia Display, and the ABCD grading system. For biomechanical analyses, the corneal biomechanical index (CBI) and tomographic biomechanical index were used. Results The mean best-corrected visual acuity was 0.01 ± 0.10 logMAR. Mean K-Max was 43.79 ± 1.12 D, mean central corneal thickness 529 ± 25 µm, mean thinnest corneal thickness 524 ± 23 µm, and mean Belin/Ambrosio Ectasia Display 1.0 ± 0.32. The mean CBI was 0.30 ± 0.21. Regular CBI values were found in six of 14 patients. The mean tomographic biomechanical index was 0.47 ± 0.22 with regular values observed in only two of 14 patients. No signs of tomographic or biomechanical abnormalities were shown in only one of 14 keratoconus fellow eyes, with regular ABCD, Belin/Ambrosio Ectasia Display, CBI and tomographic biomechanical index values. Conclusions Tomographically normal fellow eyes of keratoconus patients are rare. In these cases, a biomechanical analysis of the cornea may help detect a subclinical keratoconus. The tomographic biomechanical index was the most sensitive index to verify a mild ectasia.

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