Keratoconus Detection by Ultrasound

Study Overview
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Brief Summary
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Keratoconus (KC) is a corneal disease which will in many cases ultimately require corneal transplantation to maintain vision. Early detection, which is not possible with current technology, would allow early treatment and prevent severe damage to KC corneas inadvertently operated upon for correction of vision. The investigators' aim is to combine measurements of different properties of the cornea to develop means for early detection of KC.

Detailed Description
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Keratoconus is the most common degenerative disease affecting the cornea. As keratoconus develops, the cornea thins and bulges. Eventually, a corneal transplant may be needed to maintain vision. In its earliest stages, the disease is particularly difficult to detect. This is of great importance to the corneal refractive surgeon because surgical treatment of a keratoconic cornea will weaken it and greatly accelerate the occurrence of symptoms. Early detection of keratoconus will benefit patients because of the recent development of methods for strengthening the corneal stroma and preventing disease progression. The investigators have developed a technique based on the use of high resolution ultrasound for imaging the cornea and measuring the thickness of its component layers, including the epithelium and the stroma. In early keratoconus, as the anterior stromal surface begins to bulge forward, the epithelium will thin above the apex of the bulge and thicken around it, to maintain a smooth anterior surface. The investigators have also developed methods for characterizing the elastic properties of the cornea by inducing and measuring surface displacements in response to a pulse of acoustic radiation force. The investigators' goal is to reduce the percentage of screened cases deemed keratoconus-suspect by at least a factor of two by allowing an unambiguous diagnosis of early keratoconus. This would provide two major benefits; (1) to be able to predict eyes with higher risk of developing ectasia after corneal refractive surgery, and (2) early diagnosis would allow earlier treatment of the condition with collagen crosslinking, preserving the cornea from disease progression.

Official Title
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Early Detection of Keratoconus Using Ultrasound

Conditions
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Keratoconus

Intervention / Treatment
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* Procedure: Artemis Ultrasound Exam
* Procedure: Optical Coherence Tomography (OCT) Exam


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinical diagnosis of keratoconus (KC) or keratoconus-suspect Blood relation of person with KC Age-matched normal of KC subjects Ability to sit still in front of ultrasound unit and lie on exam table Exclusion Criteria: Other eye disease

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 65 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 |
| --- | --- |
| Keratoconus-Suspect<br>A person who has or is suspected of having keratoconus. Will have either or both Artemis-2 exam and OCT exam. | Procedure: Artemis Ultrasound Exam<br>* Ultrasound exam of both eyes using an Artemis-2 device. Exam will be performed once. Exam duration is 20 minutes per eye.<br>* Other names: High frequency ultrasound;Procedure: Optical Coherence Tomography (OCT) Exam<br>* OCT exam of both eyes. Exam will be performed once, duration is 10. I utes per eye.<br>* Other names: OCT;|
| Keratoconus-Related<br>A person who is genetically related to someone with keratoconus. Will have either or both Artemis-2 exam and OCT exam. | Procedure: Artemis Ultrasound Exam<br>* Ultrasound exam of both eyes using an Artemis-2 device. Exam will be performed once. Exam duration is 20 minutes per eye.<br>* Other names: High frequency ultrasound;Procedure: Optical Coherence Tomography (OCT) Exam<br>* OCT exam of both eyes. Exam will be performed once, duration is 10. I utes per eye.<br>* Other names: OCT;|
| Age-Matched Normal<br>A person who is approximately the same age as subjects who have been enrolled in the study. Will have either or both Artemis-2 exam and OCT exam. | Procedure: Artemis Ultrasound Exam<br>* Ultrasound exam of both eyes using an Artemis-2 device. Exam will be performed once. Exam duration is 20 minutes per eye.<br>* Other names: High frequency ultrasound;Procedure: Optical Coherence Tomography (OCT) Exam<br>* OCT exam of both eyes. Exam will be performed once, duration is 10. I utes per eye.<br>* Other names: OCT;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Differences in elastic parameters between normal and KC corneas. | The undamped vibrational frequency and damping time-constant for the anterior and posterior corneal surfaces and for Bowman's membrane will be measured. The elastic modulus will be calculated form the change in corneal thickness resulting from known radiation force. | Up to 1 year after enrollment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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keratoconus, keratoconus-suspect, ultrasound exam, acoustic radiation force ultrasound exam