A Comprehensive Assessment of Anterior Corneal Power by Different Devices

Study Overview
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Brief Summary
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To comprehensively assess the precision and agreement of anterior corneal power measurements using 8 different devices.

Detailed Description
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Volunteers with healthy corneas will be measured by different instruments to detect their anterior corneal power. Only the right eye of each subject was selected. Measurements were repeated in the second session scheduled 1 to 2 weeks later.

Official Title
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A Comprehensive Assessment of the Precision and Agreement of Anterior Corneal Power Measurements Obtained Using Different Devices

Conditions
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Myopia

Intervention / Treatment
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* Device: Corneal power measurement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy cornea, best corrected distance visual acuity (BCVA) equal to or better than 20/25, willing and able to comply with scheduled visits and other study procedures. Exclusion Criteria: History of refractive surgery or any keratoplasty procedure, use of contact lenses, history of corneal dystrophies or degenerative diseases, history of glaucoma or ocular hypertension, significant subjective dry eye symptoms, Schirmer I test results of less than 5.0 mm, tear film break-up time shorter than 5 seconds and corneal fluorescein staining positive.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

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 |
| --- | --- |
| Corneal power measurement<br>All recruited volunteers in present study, that underwent corneal power measurement with 8 different instruments | Device: Corneal power measurement<br>* All subjects will be underwent a full ophthalmic examination including vision, auto- and subjective refraction, slit-lamp examination, non-contact tonometry, corneal power measurements with the 8 devices and fundus examination.<br>* Other names: Tomey RC-5000;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Flat corneal power | The intrasession repeatability and intersession reproducibility of ﬂat corneal curvature measurements by using the 8 commercially available instruments. | 2 weeks | 
| Steep corneal power | The intrasession repeatability and intersession reproducibility of Steep corneal curvature measurements by using the 8 commercially available instruments. | 2 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vector power J0 | The intrasession repeatability and intersession reproducibility of vector power J0 measurements by using the 8 commercially available instruments. | 2 weeks | 
| Vector power J45 | The intrasession repeatability and intersession reproducibility of vector power J45 measurements by using the 8 commercially available instruments. | 2 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Anterior corneal power, Placido topographer, Scheimpﬂug, Precision, Agreement