Evolution of a Novel Optical Coherence Tomography Based Index in Diagnosing Keratoconus

Study Overview
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Brief Summary
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Comparison of corneal topography based on oct OCT principle (CASIA2) with Pentacam and Scheimpflug-based biomechanical devices (Corvis ST) in screening and diagnosing keratoconus; and evaluation of the consistency with Pentacam in measuring corneal parameters (such as curvature and thickness).

Official Title
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A Study on Evaluating the Consistency of CASIA2, Pentacam, and Corvis ST Measurement Parameters and the Diagnostic Efficacy of Early Keratoconus

Conditions
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Scansys, Pentacam, Keratoconus, Subclinical Keratoconus

Intervention / Treatment
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* Other: Pentacam, Corvis ST and CASIA2


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Best corrected visual acuity (BCVA) ≥ 20/20; No other eye diseases except myopia and astigmatism; The cornea was transparent, and there was no cloud or pannus; Exclusion Criteria: The presence of ocular diseases other than myopia and keratoconus; Ocular trauma; Previous ocular surgery; 4 Patients were required to stop wearing soft contact lenses for at least 2 weeks and rigid contact lenses for at least 4 weeks before examination; 6. Pregnant and lactating women;
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Normal control group<br> | Other: Pentacam, Corvis ST and CASIA2<br>* morphological and biomechanical parameters of corneal were obtain by CASIA2, Pentacam and Corvis ST<br>|
| Subclinical keratoconus<br> | Other: Pentacam, Corvis ST and CASIA2<br>* morphological and biomechanical parameters of corneal were obtain by CASIA2, Pentacam and Corvis ST<br>|
| Keratoconus<br> | Other: Pentacam, Corvis ST and CASIA2<br>* morphological and biomechanical parameters of corneal were obtain by CASIA2, Pentacam and Corvis ST<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| screening and diagnosis ability | Evaluate the sensitivity and specificity of parameters measured by CASIA2, Pentacam in diagnosing keratoconus using Receiver operating characteristic curves (ROC), and compare the Ectasia Screening Similarity（ESS）and D-value diagnostic efficacy using Area under the ROC curve (AUROC). Use the Delong test to compare the accuracy of various parameters in diagnosing early keratoconus. | one year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measurement consistency | The independent sample T-test is used to compare inter- group differences in baseline data. Use independent sample T-test and One-way ANOVA to evaluate the consistency of the measurement results (anterior and posterior corneal curvature, corneal refractive index, CCT) obtained by CASIA2 and Pentacam.Finally, the ultimate outcome（such ad：K1 K2 KMax CCT） indicates that the P-value between the two devices is less than 0.05 and ICC-value is more than 0.75. | one year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Scansys, Pentacam, Keratoconus, subclinical keratoconus