Clinical trial NCT00777322: T-Cat Laser & Cross-linking for Keratoconus
Official title: Pilot Study of Excimer Laser Topography-Computer Assisted Treatment (T-Cat) Combined With Corneal Collagen Cross-linking With Riboflavin and UV Light
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Keratoconus
Pellucid Marginal Degeneration
Keywords: keratoconus
pellucid marginal degeneration
corneal ectasia
collagen cross-linking
riboflavin
UV light
excimer laser
Topography-Computer Assisted Treatment (T-Cat)
Wavelight Allegretto laser
Lead sponsor: Moorfields Eye Hospital NHS Foundation Trust
Sponsor class: OTHER
Collaborators: name: Accuvision Laser Eye Clinics
name: Carleton Optical Equipment Ltd.
name: Bon Optics
name: Sooft Italia
First posted: 2008-10-22
Enrollment: 15
Sex: ALL
Minimum age (years): 18
Maximum age (years): 50
Standard ages: ADULT
Accepts healthy volunteers: no
Allocation: NON_RANDOMIZED
Intervention model: SINGLE_GROUP
Primary purpose: TREATMENT

Brief 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.

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.

Eligibility criteria: 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.

Primary outcomes:
measure: The difference in the pre- and post-operative unaided visual acuity, best corrected visual acuity, and refraction.
timeFrame: At six months
Secondary outcomes:
measure: Corneal topographic profile.
timeFrame: At six months
Other outcomes:
Locations:
city: London
country: United Kingdom
facility: Moorfields Eye Department at St George's Hospital
Study officials:
affiliation: Moorfields Eye Hospital NHS Foundation Trust
name: Chad K Rostron, MB BS
role: PRINCIPAL_INVESTIGATOR
References: