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Clinical Trial Details — Status: Completed

Administrative data

NCT number NCT00777322
Other study ID # REC Ref: 07/H0721/94
Secondary ID
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


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
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