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’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<0.01; P>0.05, two-way ANOVA) with BAC and CV <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<0.01; P>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 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 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 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 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.

Central Corneal Thickness Measurements Using Orbscan II Scanning Slit Topography, Noncontact Specular Microscopy, and Ultrasonic Pachymetry in Eyes With Keratoconus

Cornea ◽  
2005 ◽  
Vol 24 (8) ◽  
pp. 967-971 ◽  
Author(s):  
Keisuke Kawana ◽  
Kazunori Miyata ◽  
Tadatoshi Tokunaga ◽  
Takahiro Kiuchi ◽  
Takahiro Hiraoka ◽  
...  
Keyword(s):  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Specular Microscopy ◽  
Orbscan Ii ◽  
Thickness Measurements ◽  
Ultrasonic Pachymetry

scholarly journals Repeatability of central and peripheral corneal thickness measurements with the iVue100 optical coherence tomographer

2016 ◽  
Vol 75 (1) ◽  
Author(s):  
Nishanee Rampersad ◽  
Rekha Hansraj
Keyword(s):  
Linear Regression ◽  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Optical Coherence ◽  
Contact Lens Wear ◽  
Mean Differences ◽  
The University ◽  
Thickness Measurements ◽  
Sd Oct

Background: Accurate assessment of corneal thickness is essential in corneal refractive surgery, contact lens wear and corneal pathology.Aim: To assess the repeatability (intra-observer, inter-observer and inter-session) of central (0 mm – 2 mm), mid-peripheral (2 mm – 5 mm) and peripheral (5 mm – 6 mm) corneal thickness measurements using the iVue 100 spectral domain optical coherence tomographer (SD-OCT).Setting: Optometry Eye Clinic at the University of KwaZulu-Natal (UKZN).Methods: Corneal thickness measurements were taken on 50 healthy participants by two observers independently. A second set of readings was taken by one observer on another session. Repeatability was assessed using Bland–Altman analysis, the intraclass correlation coefficient, coefficient of variation and one-way analysis of variance (ANOVA) analysis.Results: For all corneal regions, the intraclass correlation coefficients for observer one ranged from 0.942 to 0.999 and that for observer two ranged from 0.946 to 0.999, indicating good intra-observer repeatability. Using linear regression, the corneal thickness measurements were found to be comparable (within 1 µm of each other) in all regions with the exception of the nasal and temporal mid-periphery and periphery. The inter-session repeatability was based on the measurements of observer one only with the mean differences ranging from 0.02 µm to 0.63 µm. Linear regression revealed no significant differences between session 1 and session 2 (p > 0.05) except for the measurement of minimum corneal thickness.Conclusion: This study found evidence of good intra-observer, inter-observer and intersession repeatability of central, mid-peripheral and peripheral corneal measurements with the iVue 100 SD-OCT.

scholarly journals Evaluation of the Repeatability and the Reproducibility of AL-Scan Measurements Obtained by Residents

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mehmet Kola ◽  
Hikmet Duran ◽  
Adem Turk ◽  
Suleyman Mollamehmetoglu ◽  
Ahmet Kalkisim ◽  
...  
Keyword(s):  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Anterior Chamber Depth ◽  
Ocular Biometry ◽  
Iol Calculation ◽  
Iol Power ◽  
Good Repeatability ◽  
Repeatability And Reproducibility ◽  
Biometric Measurements ◽  
Power Measurements

Purpose. To assess the repeatability and reproducibility of ocular biometry and intraocular lens (IOL) power measurements obtained by ophthalmology residents using an AL-Scan device, a novel optical biometer.Methods. Two ophthalmology residents were instructed regarding the AL-Scan device. Both performed ocular biometry and IOL power measurements using AL-Scan, three times on each of 128 eyes, independently of one another. Corneal keratometry readings, horizontal iris width, central corneal thickness, anterior chamber depth, pupil size, and axial length values measured by both residents were recorded together with IOL power values calculated on the basis of four different IOL calculation formulas (SRK/T, Holladay, and HofferQ). Repeatability and reproducibility of the measurements obtained were analyzed using the intraclass correlation coefficient (ICC).Results. Repeatability (ICC, 0.872-0.999 for resident 1 versus 0.905-0.999 for resident 2) and reproducibility (ICC, 0.916-0.999) were high for all biometric measurements. Repeatability (ICC, 0.981-0.983 for resident 1 versus 0.995-0.996 for resident 2) and reproducibility were also high for all IOL power measurements (ICC, 0.996 for all).Conclusions. The AL-Scan device exhibits good repeatability and reproducibility in all biometric measurements and IOL power calculations, independent of the operator concerned.

Repeatability of whole-cornea measurements using a new swept-source optical coherence tomographer

2020 ◽  
pp. 112067212094402
Author(s):  
Pedro Tañá-Rivero ◽  
Salvador Aguilar-Córcoles ◽  
Ramón Ruiz-Mesa ◽  
Robert Montés-Micó
Keyword(s):  
Spherical Aberration ◽  
Intraclass Correlation ◽  
Repeated Measurements ◽  
Optical Coherence ◽  
Swept Source ◽  
Corneal Aberrations ◽  
Good Repeatability ◽  
Best Fit ◽  
High Repeatability ◽  
Anterior Posterior

Purpose: The aim of this study was to evaluate the repeatability of several corneal parameters provided by a high-resolution swept-source optical coherence tomographer (SS-OCT). Methods: One eye from each of 74 patients was measured five times consequently using the ANTERION SS-OCT. The following corneal parameters were analyzed: average, steep and flat keratometry (K), astigmatism for anterior, posterior and total at 3-mm, average K and astigmatism at 6-mm, anterior and posterior eccentricity, higher-order aberrations (HOA) and spherical aberration ([Formula: see text]), and anterior and posterior best-fit sphere at 8-mm. The intrasubject standard deviation (Sw), coefficient of variation (CoV), coefficient of repeatability (CoR) and intraclass correlation coefficient (ICC) were calculated for each parameter to assess the repeatability. Results: We have not found statistically significant differences between repeated measurements ( p > 0.05). Repeatability was good considering the different metrics used. Sw values were <0.09, varying from 0.035 (posterior average K at 6-mm) to 0.0878 (anterior flat K at 3-mm). CoV values were also low and similar among the different parameters (from 0.08% to 0.21%), except for anterior, posterior and total astigmatism (from 2.25% to 8.46%). Both anterior and posterior eccentricity, and corneal aberrations (HOA and [Formula: see text]) CoV values were also high. The CoR values were low for all parameters showing those related to the posterior cornea the lowest values (about 0.01). ICC values were >0.98. Conclusions: The ANTERION SS-OCT showed good repeatability when reconstructed different parameters for the whole cornea. This device produces measurements with high repeatability that could be useful for clinical research.

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