T-Cat Laser & Cross-linking for Keratoconus

Keratoconus Clinical Trial

— T-Cat  

Official title:

Pilot Study of Excimer Laser Topography-Computer Assisted Treatment (T-Cat) Combined With Corneal Collagen Cross-linking With Riboflavin and UV Light

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00777322
• Other study ID #: REC Ref: 07/H0721/94
• Status: Completed
• Phase: N/A
• First received: October 21, 2008
• Last updated: July 20, 2011
• Start date: October 2008
• Est. completion date: October 2010

Study information

• Verified date: April 2009
• Source: Moorfields Eye Hospital NHS Foundation Trust
• Contact: n/a
• Is FDA regulated: No
• Health authority: United Kingdom: Research Ethics Committee
• Study type: Interventional

Clinical Trial Summary

The purpose of this study is 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 in the treatment of keratoconus.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 15
• Est. completion date: October 2010
• Est. primary completion date: October 2010
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years to 50 Years

Eligibility

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 Design

Allocation: Non-Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Keratoconus
• Pellucid Marginal Degeneration

Intervention

Procedure:
• Excimer laser ablation, and collagen cross-linking
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.

Locations

Country	Name	City	State
United Kingdom	Moorfields Eye Department at St George's Hospital	London

Sponsors (5)

Lead Sponsor	Collaborator
Moorfields Eye Hospital NHS Foundation Trust	Accuvision Laser Eye Clinics, Bon Optics, Carleton Optical Equipment Ltd., Sooft Italia

Country where clinical trial is conducted

United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	The difference in the pre- and post-operative unaided visual acuity, best corrected visual acuity, and refraction.		At six months	Yes
Secondary	Corneal topographic profile.		At six months	Yes

External Links

•   Full patient information sheet
•   Overview of the treatment concept