- ICH GCP
- US Clinical Trials Registry
- Clinical Trial NCT00777322
T-Cat Laser & Cross-linking for Keratoconus (T-Cat)
Pilot Study of Excimer Laser Topography-Computer Assisted Treatment (T-Cat) Combined With Corneal Collagen Cross-linking With Riboflavin and UV Light
Study Overview
Status
Conditions
Intervention / Treatment
Detailed Description
Theoretical framework:
Corneal ectasia is a relative weakness in the structure of the cornea, which produces a progressive change in its shape with resultant visual distortion.
Excimer laser surface ablation can be used to re-shape the corneal profile. When the corneal shape is very irregular, corneal topography data gives the best information as to how to re-shape the cornea into a normal profile, and this Topography-Computer Assisted Treatment (T-Cat) will be used to modulate the surface corneal shape.
It is known that collagen cross-linking in the cornea occurs naturally with age, and in diabetes, both of which seem to prevent progressive ectasia. Corneal collagen cross-linking with riboflavin has been shown to stabilize the cornea in keratoconus, and prevents progression of the disease. If cross-linking is performed at that moment that the cornea has been re-shaped by T-Cat treatment, it should help prevent the corneal thinning resultant from the laser treatment from destabilising the cornea and causing progressive ectasia.
Purpose:
To determine whether excimer laser corneal surface ablation (T-Cat) can be safely combined with simultaneous corneal collagen cross-linking treatment to produce an improved and stable corneal profile.
Design:
Prospective, interventional trial.
Study Type
Enrollment (Actual)
Phase
- Not Applicable
Contacts and Locations
Study Locations
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London, United Kingdom, SW17 0QT
- Moorfields Eye Department at St George's Hospital
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Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Genders Eligible for Study
Description
Inclusion Criteria:
- Patients with known keratoconus or pellucid marginal degeneration.
Exclusion Criteria:
- Age < 18 years > 50 years.
- Minimal corneal pachymetry in eye to be treated of < 400μ.
- Evidence of other corneal disease in the eye to be treated (e.g. Herpes simplex keratitis).
- Women who are pregnant or nursing at the time of the initial treatment.
- Presence of significant central corneal opacity.
- Patients unwilling to not wear rigid contact lenses in the eye to be operated on for at least one month before baseline examination, and for the first six months post-operatively.
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Treatment
- Allocation: Non-Randomized
- Interventional Model: Single Group Assignment
- Masking: None (Open Label)
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
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Experimental: Interventional study
Patients with known keratoconus or pellucid marginal degeneration will be invited to join the study.
The study is partly a continuation in the management of patients who have had previous keratophakia, who will have near-normal or supra-physiological levels of corneal thickness.
It is also intended for patients with relatively mild keratoconus who have sufficient corneal thickness to allow a limited laser ablation whilst still leaving a residual stromal bed of at least 350μ.
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Surgery is performed with topical anaesthesia.
The central corneal epithelium is removed.
Excimer laser ablation is applied (typically 15-30 seconds).
Residual bed thickness is checked with an ultrasonic pachymeter.
Topical application of riboflavin 0.1% in dextran is commenced at 5 minute intervals.
When an adequate saturation of the anterior chamber with riboflavin has been achieved, cross-linking treatment will proceed.
Output from the UV light generating equipment is measured with a UV light meter and set at 3mW/cm².
Thirty minutes of treatment is given, interrupted at five minute intervals by the application of more topical riboflavin drops.
Finally the eye has a bandage soft contact lens placed, with preservative free topical antibiotic, steroid, and cycloplegic drop application.
Other Names:
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What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Time Frame |
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The difference in the pre- and post-operative unaided visual acuity, best corrected visual acuity, and refraction.
Time Frame: At six months
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At six months
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Secondary Outcome Measures
Outcome Measure |
Time Frame |
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Corneal topographic profile.
Time Frame: At six months
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At six months
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Collaborators and Investigators
Investigators
- Principal Investigator: Chad K Rostron, MB BS, Moorfields Eye Hospital NHS Foundation Trust
Study record dates
Study Major Dates
Study Start
Primary Completion (Actual)
Study Completion (Actual)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Estimate)
Study Record Updates
Last Update Posted (Estimate)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Keywords
Additional Relevant MeSH Terms
Other Study ID Numbers
- REC Ref: 07/H0721/94
This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.
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Clinical Trials on Excimer laser ablation, and collagen cross-linking
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Shahid Beheshti University of Medical SciencesUnknownKeratoconusIran, Islamic Republic of
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Sun Yat-sen UniversityUnknownProgressive KeratoconusChina