Keratoconus
Conditions
Keywords
keratoconus, keratoconus-suspect, ultrasound exam, acoustic radiation force ultrasound exam
Brief summary
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
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.
Interventions
Ultrasound exam of both eyes using an Artemis-2 device. Exam will be performed once. Exam duration is 20 minutes per eye.
OCT exam of both eyes. Exam will be performed once, duration is 10. I utes per eye.
Sponsors
Study design
Eligibility
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Differences in elastic parameters between normal and KC corneas. | Up to 1 year after enrollment | 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. |
Countries
United Kingdom, United States