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.

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 Corneal Biomechanical Parameters and Central Corneal Thickness in Glaucoma Patients, Glaucoma Suspects, and a Healthy Population

2021 ◽  
Vol 10 (12) ◽  
pp. 2637
Author(s):  
Mª. Ángeles del Buey-Sayas ◽  
Elena Lanchares-Sancho ◽  
Pilar Campins-Falcó ◽  
María Dolores Pinazo-Durán ◽  
Cristina Peris-Martínez
Keyword(s):  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Mean Difference ◽  
The Other ◽  
Control Group ◽  
Healthy Population ◽  
Diagnostic Categories ◽  
Significant Difference ◽  
Biomechanical Parameters ◽  
The Mean

Purpose: To evaluate and compare corneal hysteresis (CH), corneal resistance factor (CRF), and central corneal thickness (CCT), measurements were taken between a healthy population (controls), patients diagnosed with glaucoma (DG), and glaucoma suspect patients due to ocular hypertension (OHT), family history of glaucoma (FHG), or glaucoma-like optic discs (GLD). Additionally, Goldmann-correlated intraocular pressure (IOPg) and corneal-compensated IOP (IOPcc) were compared between the different groups of patients. Methods: In this prospective analytical-observational study, a total of 1065 patients (one eye of each) were recruited to undergo Ocular Response Analyzer (ORA) testing, ultrasound pachymetry, and clinical examination. Corneal biomechanical parameters (CH, CRF), CCT, IOPg, and IOPcc were measured in the control group (n = 574) and the other groups: DG (n = 147), FHG (n = 78), GLD (n = 90), and OHT (n = 176). We performed a variance analysis (ANOVA) for all the dependent variables according to the different diagnostic categories with multiple comparisons to identify the differences between the diagnostic categories, deeming p < 0.05 as statistically significant. Results: The mean CH in the DG group (9.69 mmHg) was significantly lower compared to controls (10.75 mmHg; mean difference 1.05, p < 0.001), FHG (10.70 mmHg; mean difference 1.00, p < 0.05), GLD (10.63 mmHg; mean difference 0.93, p < 0.05) and OHT (10.54 mmHg; mean difference 0.84, p < 0.05). No glaucoma suspects (FHG, GLD, OHT groups) presented significant differences between themselves and the control group (p = 1.00). No statistically significant differences were found in the mean CRF between DG (11.18 mmHg) and the control group (10.75 mmHg; mean difference 0.42, p = 0.40). The FHG and OHT groups showed significantly higher mean CRF values (12.32 and 12.41 mmHg, respectively) than the DG group (11.18 mmHg), with mean differences of 1.13 (p < 0.05) and 1.22 (p < 0.001), respectively. No statistically significant differences were found in CCT in the analysis between DG (562 μ) and the other groups (control = 556 μ, FHG = 576 μ, GLD = 569 μ, OHT = 570 μ). The means of IOPg and IOPcc values were higher in the DG patient and suspect groups than in the control group, with statistically significant differences in all groups (p < 0.001). Conclusion: This study presents corneal biomechanical values (CH, CRF), CCT, IOPg, and IOPcc for diagnosed glaucoma patients, three suspected glaucoma groups, and a healthy population, using the ORA. Mean CH values were markedly lower in the DG group (diagnosed with glaucoma damage) compared to the other groups. No significant difference was found in CCT between the DG and control groups. Unexpectedly, CRF showed higher values in all groups than in the control group, but the difference was only statistically significant in the suspect groups (FHG, GLD, and OHT), not in the DG group.

scholarly journals Comparison of IOP Measurement by Goldmann Applanation Tonometer, ICare Rebound Tonometer, and Tono-Pen in Keratoconus Patients after MyoRing Implantation

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Mahmoud Rateb ◽  
Mahmoud Abdel-Radi ◽  
Zeiad Eldaly ◽  
Mohamed Nagy Elmohamady ◽  
Asaad Noor El Din
Keyword(s):  
Central Corneal Thickness ◽  
Pearson Correlation ◽  
Corneal Thickness ◽  
Altman Analysis ◽  
Bland Altman Analysis ◽  
Rebound Tonometer ◽  
Goldmann Applanation Tonometer ◽  
Significant Difference ◽  
Applanation Tonometer ◽  
Icare Rebound Tonometer

Purpose. To evaluate the different IOP readings by Goldmann applanation tonometer (GAT), ICare rebound tonometer, and Tono-Pen in keratoconus patients after MyoRing implantation. To assess the influence of central corneal thickness (CCT) and thinnest corneal location (TCL) on IOP measurements by different tonometers. Setting. Prospective observational study was conducted in two private centers in Egypt from February 2015 to November 2016. Methods. Seventeen eyes of 10 patients suffering from keratoconus and who underwent MyoRing implantation were recruited. All subjects underwent GAT, ICare, and Tono-Pen IOP measurements in random order. Central corneal thickness and thinnest corneal location were assessed by Pentacam. Difference in mean in IOP readings was assessed by T-test. Correlation between each pair of devices was evaluated by Pearson correlation coefficient. The Bland–Altman analysis was used to assess intertonometer agreement. Results. Seventeen eyes (10 patients) were evaluated. The mean IOP reading was 13.9 ± 3.68, 12.41 ± 2.87, and 14.29 ± 1.31 mmHg in GAT, ICare, and Tono-Pen group, respectively. There was a significant difference between IOP readings by GAT/ICare and Tono-Pen/ICare (p value: 0.032 and 0.002, respectively) with no significant difference between GAT/Tono-Pen (p value: 0.554). Mean difference in IOP measurements between GAT/ICare was 1.49 ± 2.61 mmHg, Tono-Pen/ICare was 1.89 ± 2.15 mmHg, and GAT/Tono-Pen was −0.39 ± 2.59 mmHg. There was no significant correlation between the difference in IOP readings among any pair of devices and CCC or TCL. The Bland–Altman analysis showed a reasonable agreement between any pair of tonometers.

Variation in Cervical Length over Time during a Single Transvaginal Ultrasound Examination

2018 ◽  
Vol 36 (08) ◽  
pp. 781-784
Author(s):  
Katherine A. Connolly ◽  
Luciana Vieira ◽  
Elizabeth M. Yoselevsky ◽  
Stephanie Pan ◽  
Joanne L. Stone
Keyword(s):  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Ultrasound Examination ◽  
Transvaginal Ultrasound ◽  
Intraclass Correlation ◽  
Cervical Length ◽  
Linear Mixed Effect Model ◽  
Mixed Effect ◽  
Time Points ◽  
Significant Difference

Objective To quantify the degree of change in cervical length (CL) over a 3-minute transvaginal ultrasound. Study Design We conducted a prospective observational study of nulliparous patients who underwent routine transvaginal CL screening at the time of their second-trimester ultrasound. We recorded CL at four time points (0, 1, 2, 3 minutes) and compared these values to determine the minute-to-minute change within a single patient. Results A total of 771 patients were included. The mean gestational age was 20.8 weeks (±0.84). We used a linear mixed effect model to assess if each minute during the ultrasound is associated with a change in CL. The intraclass correlation coefficient between minute 0 to minute 3 was 0.82 (95% confidence interval: 0.80, 0.84). This indicates that there is a relatively high within-patient correlation in CL during their ultrasound. Additionally, we stratified patients based on their starting CL; the intraclass correlation coefficient remained high for all groups. We additionally compared CL at each minute. Although there is a statistically significant difference between several time points, the actual difference is small and not clinically meaningful. Conclusion The variation in CL over a 3-minute transvaginal ultrasound examination is not clinically significant. It may be reasonable to conduct this examination over a shorter period.

Clinical evaluation of the repeatability of ocular aberrometry obtained with a new pyramid wavefront sensor

2018 ◽  
Vol 29 (6) ◽  
pp. 585-592 ◽  
Author(s):  
Ana B Plaza-Puche ◽  
Liberdade C Salerno ◽  
Francesco Versaci ◽  
Daniel Romero ◽  
Jorge L Alio
Keyword(s):  
Standard Deviation ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Pupil Size ◽  
Pupil Diameter ◽  
Intraclass Correlation ◽  
Wavefront Sensor ◽  
Mean Square ◽  
The Subject ◽  
Healthy Eyes

Purpose:To evaluate the intrasubject repeatability of the ocular aberrometry obtained with a new ocular pyramidal aberrometer technology in a sample of normal eyes.Methods:A total of 53 healthy eyes of 53 subjects with ages ranging from 18 to 45 years were included in this study. In all cases, three consecutive acquisitions were obtained. Intrasubject repeatability of the measurements with a pyramidal aberrometer was calculated. Intrasubject repeatability for 4.0- and 6.0-mm pupils was evaluated within the subject standard deviation (Sw) and intraclass correlation coefficient.Results:Low values of the Swand intraclass correlation coefficient outcomes close to 1 were observed for the sphere and cylinder at 3.0-mm pupil size. Most low Swand intraclass correlation coefficient values close to 1 were observed for total, low-order aberrations and higher-order aberrations root mean square and for each Zernike coefficient analysis (intraclass correlation coefficient ⩾0.798) at 4.0-mm pupil size, with more limited outcomes for the aberrometric coefficient of Z(4, 4) with an intraclass correlation coefficient of 0.683. For a 6.0 mm pupil diameter, low Swand intraclass correlation coefficient values close to 1 were observed for all aberrometric parameters or Zernike coefficients analyzed (intraclass correlation coefficient ⩾0.850).Conclusion:The new pyramidal aberrometer Osiris provides repeatable and consistent measurements of ocular aberrometry measurements in normal eyes.

scholarly journals Effect of Desonide 0.25% Ophthalmic Solution on Central Corneal Thickness and Intraocular Pressure of Patients with Allergic Conjunctivitis

1970 ◽  
Vol 12 (3) ◽  
pp. 156-158
Author(s):  
Ozlem Gurses Sahin
Keyword(s):  
Intraocular Pressure ◽  
Allergic Conjunctivitis ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Ophthalmic Solution ◽  
Applanation Tonometry ◽  
Goldmann Applanation Tonometry ◽  
Mean Values ◽  
Conjunctival Hyperaemia ◽  
Significant Difference

Aim: To evaluate whether a significant difference exists between the initial and final mean central corneal thickness that might affect Goldmann applanation tonometer recordings of patients with allergic conjunctivitis treated with desonide 0.25% ophthalmic solution, and to determine the effect of desonide on intraocular pressure by using adjusted intraocular pressure values.Methods: This double-blind randomised placebo-controlled trial enrolled 30 patients (60 eyes) with allergic conjunctivitis. Patients were randomly assigned to receive desonide to 1 eye (study eye) and preservative-free tear supplement (Tears Naturale Free®) to the other eye (control eye) 3 times daily for 3 weeks. Goldmann applanation tonometry and central corneal thickness of both eyes were recorded on the day of presentation and 3 weeks later.Results: Regression of itching, tearing, conjunctival hyperaemia, and tarsal conjunctival papillary reaction were noted in the study eyes after 3 weeks of treatment. The control eyes showed mild regression of pruritis, tearing, conjunctival hyperaemia, and tarsal conjunctival papillary reaction after 3 weeks. There was a significant difference between the initial and final mean central corneal thickness values for the study eyes (p = 0.003). There were no statistically significant differences between the initial and final mean values of Goldmann applanation tonometry and adjusted intraocular pressure for the study eyes. No statistically significant differences were found between the initial and final mean values of any of the parameters for the control eyes.Conclusion: Inflammation-induced increase in central corneal thickness of patients with allergic conjunctivitis treated with desonide showed statistically significant regression. However, this regression did not significantly affect Goldmann applanation tonometry and adjusted intraocular pressure values of the treated eyes.

scholarly journals Usefulness of the Non-Contact Tonometry in Out-Patient Screening

2016 ◽  
Vol 15 (2) ◽  
Author(s):  
Satheesh Solomon T Selvin ◽  
Chris Elsa Samson Jacob ◽  
Thomas Kuriakose
Keyword(s):  
Central Corneal Thickness ◽  
Care Center ◽  
Corneal Thickness ◽  
Tertiary Care ◽  
Cross Sectional Study ◽  
Applanation Tonometry ◽  
Cross Sectional ◽  
Significant Difference ◽  
Iop Measurement ◽  
The Mean

Purpose: Goldmann applanation tonometry (GAT) is considered the gold standard for Intraocular Pressure (IOP) measurement. It has the disadvantages of being a contact device, need for a slit-lamp, non-portability and need of a skilled examiner. Many hospitals are using a Non Contact Tonometry (NCT) as a screening device to save clinician time, however the usefulness is not proved in terms of reliability. This study was aimed to determine the usefulness of the Air-puff tonometer (TONOREF NIDEK II, NIDEK CO., LTD., JAPAN) over a GAT in a tertiary care center. Design: Cross-sectional Study Methods: This was a cross-sectional, non interventional observational study conducted on 224 eyes (right eye) from 224 patients. All patients underwent the IOP measurement with both methods and a central corneal thickness (CCT) measured. The data was analyzed using SPSS 20.0 software. Results: The mean age of the patients was 40.3±11.29 years. There was a statistically significant difference (p<0.001) between the mean NCT and GAT readings which persisted even after correction for central corneal thickness. The correlation between NCT and GAT using Pearson’s correlation coefficient was strong irrespective of the corrections for their corneal thickness (r = 0.751 and 0.718 for uncorrected and corrected values respectively). The correlation of the individual clinicians for the readings varied from moderate to strong. The ROC curve showed the best sensitivity and specificity to occur at around 13 to 14 mmHg. Conclusion: NCT seems to overestimate the IOP at low ranges as compared to the GAT and underestimate at higher ranges. The crossover of the values is seen between 12 to 13 mmHg.  The clinician should do an individualized analysis of his/her GAT measurements to the readings of the NCT machine at the clinic to obtain clinician specific nomogram. 

scholarly journals The pattern of central corneal thickness in patients attending a Tertiary Hospital in Dar-Es-Salaam

2021 ◽  
Vol 9 (2) ◽  
pp. 127-133
Author(s):  
Annamary Stanislaus ◽  
Ntsilane Susan Mosenene ◽  
Celina Mhina ◽  
John Stanslaus Kisimbi ◽  
Frederick Robert Burgess ◽  
...  
Keyword(s):  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Dar Es Salaam ◽  
Applanation Tonometry ◽  
P Value ◽  
Muhimbili National Hospital ◽  
National Hospital ◽  
Cross Sectional ◽  
Significant Difference ◽  
The Mean

Background: Central Corneal Thickness (CCT) is an indicator of corneal health status as well as being an essential tool in assessment and management of corneal diseases. It is an important factor in the diagnosis and management of glaucoma as it affects the measurement of intraocular pressure. However, the pattern of central corneal thickness in our population is not known. Our study aimed to describe the CCT measurements and their variation with age and sex among patients attending the eye clinic at Muhimbili National Hospital (MNH), in Dar es Salaam, Tanzania. Methodology: A hospital-based descriptive, cross-sectional study used convenient sampling to recruit adult patients aged 18 years and above, presenting to the MNH between August 2016 and January 2017.Visual acuity assessment, Goldman applanation tonometry and CCT assessment using an ultrasound pachymeter were performed. Patients with previous intraocular surgery were excluded. Results: A total of 398 patients (208 males and 190 females) were recruited. The mean CCT was 526.64±38.30 µm; being 523.99±38.20 µm for males and 529.7±38.3 µm for females. 226 (56.85%) had CCT of less than 520 µm.There was no statistically significant difference in CCT between gender. The proportion of patients with thinner CCT increased with increasing age from 25.8% in those < 30 years to 75% in those aged 71years and above. The mean CCT decreased with increasing age with P-value<0.001. Conclusion: The average CCT in patients attending Muhimbili National Hospital is 526.64 µm (SD 38.30) which is generally thin, inversely proportion to age and similar that of other Africans and African-Americans. This finding has implications for the management of glaucoma in this population.

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