Combined CXL//UV and PRK or LASIK in Forme Fruste Keratoconus or Eyes With Potential Risk of Ectasia

Study Overview
=================
Brief Summary
-----------------
This study is being performed to evaluate the efficacy of ultraviolet-A (UVA)-induced cross-linking of corneal collagen (CXL) in strengthening and optimizing the biomechanical and biochemical stability of the cornea in patients with fruste keratoconus (FFKC), corneas that are suspicious for FFKC and corneas thought to be at higher risk of developing ectasia that will be undergoing laser vision correction.

Detailed Description
-----------------
This study is being performed to evaluate the efficacy of ultraviolet-A (UVA)-induced cross-linking of corneal collagen (CXL) in strengthening and optimizing the biomechanical and biochemical stability of the cornea in patients with fruste keratoconus (FFKC), corneas that are suspicious for FFKC and corneas thought to be at higher risk of developing ectasia that will be undergoing laser vision correction. CXL is thought to augment the tectonic strength of the cornea by using UVA light and the photo-mediator riboflavin. The purpose of this non-randomized study is to compare the visual results of patients who are suspicious for having an increased risk of ectasia with laser vision correction compared to a group of patients that does not have these risk factors. All excimer laser ophthalmic procedures currently being performed to correct myopia, hyperopia or astigmatism with FDA approved excimer lasers do so by removing corneal tissue and thereby potentially weakening the cornea biomechanically. This can result in ectasia even in patients without pre-existing risk factors.

Official Title
-----------------
Combined Collagen Crosslinking/Ultraviolet-A and Photorefractive Keratectomy or LASIK in Forme Fruste Keratoconus or Eyes With Potentially Elevated Risk of Ectasia

Conditions
-----------------
Fruste Keratoconus, Risk of Ectasia

Intervention / Treatment
-----------------
* Device: Corneal Cross-Linking
* Drug: Riboflavin


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: 18 years of age or older Up to 4 potential risk factors for ectasia A. Abnormal Topography: Consistent with forme fruste keratoconus, forme fruste pellucid marginal degeneration, asymmetric astigmatism, or increased posterior float/posterior corneal surface shape. B. Corneal thickness of 500 microns or less, as measured by ultrasound, Orbscan, or Pentacam C. Age 18 to 25 D. Planned Residual stromal bed between 250 and 300 microns Ability to provide written informed consent Likely to complete all study visits Best spectacle-corrected visual acuity (BSCVA) of 20/25 in each eye Patients with and without previous laser vision correction are eligible for participation. Exclusion Criteria: Frank keratoconus, Pellucid, or Post-LASIK ectasia Less than 20/30 BSCVA in either eye Corneal scarring that markedly affects vision Contraindications to any study medications or their components Pregnancy or breast feeding Active Herpes Corneal Disease

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| low risk subjects for developing post-operative ectasia<br>Patients undergoing vision correction surgery who are not at a higher risk for developing post-op ectasia | Device: Corneal Cross-Linking<br>* Corneal cross-linking procedure conducted during vision correction surgery.<br>Drug: Riboflavin<br>* Riboflavin will be instilled prior to corneal cross linking.<br>|
| Subjects at Risk for Ectasia<br>Patients undergoing vision correction surgery who are at a higher risk for developing post-operative ectasia | Device: Corneal Cross-Linking<br>* Corneal cross-linking procedure conducted during vision correction surgery.<br>Drug: Riboflavin<br>* Riboflavin will be instilled prior to corneal cross linking.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative Best-Corrected Visual Acuity |  | Month 9 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Residual Refractive error at the 1, 3 and 6 month visits |  | Months 1, 3, and 6 | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
fruste keratoconus, ectasia