Keratoconus
Conditions
Keywords
Cornea, Keratoconus, Ectasia, Riboflavin, Collagen cross-linking
Brief summary
The purpose of this study is to determine the effectiveness of collagen cross-linking in the cornea in halting the progression and possibly partially reversing the effects of keratoconus. Keratoconus is a progressive weakening in the cornea that causes irregular astigmatism and thinning of the cornea. The overall effect is reduction of vision, and in more advanced cases, scarring of the cornea that may lead to the need for corneal transplantation. Cross-linking has been shown increase the rigidity of the cornea. The patients would be treated once and then followed over 24 months. .
Detailed description
The goal is for two groups of approximately 66 patients to be included in the study. One eye from the first group will undergo treatment, while the second group of age matched individuals will serve as a control. It will be a prospective, randomized, blinded study. Each patient will be randomized at the beginning of enrollment in the study and will receive a randomization number. The following parameters will be followed: 1. Best corrected spectacle acuity (BCSA) 2. The steepest keratometry measurement (KMax) as measured by computerized corneal topography 3. Apical corneal thickness 4. Corneal mechanical resistance. These measurements will be repeated at 1 month, 3 months, 6 months, 12, 18, and 24 months following treatment.
Interventions
DRUGRiboflavin-5-phosphate
Riboflavin 0.1% (10 mg riboflavin-5-phosphate in 10 ml dextran T-500 20% solution, supplied in a sterile, single dose container) will be applied to the cornea every 2-3 minutes for 15 minutes prior to starting UV irradiation. The UV irradiation will be given in six 5 minute intervals. Additional riboflavin will be administered following each 5 minute UV treatment.
DRUGSham cross-linking
Topical anesthesia (lidocaine jelly 2%) will be used. Differing from the treatment group, no epithelium will be debrided, but instead, this step will be skipped and 2% methylcellulose solution with 1% sodium fluorescein will be applied to the cornea every 5 minutes for 15 minutes, and then every 5 minutes during the sham UV treatment. The patient will be placed under the UV device, and the aiming beam applied.
Sponsors
University at Buffalo
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Caregiver, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
16 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* no prior history of ocular surgery * treatment eye must have a maximum corneal power of between 47 D and 60 diopters * corneal thickness must be greater than 400 µ * absence of corneal scarring * patients must meet the diagnostic criteria for keratoconus, which include one or more of the following features: * high myopia * corneal ectasia as viewed by slit-lamp exam or measured by pachometry * Vogt's striae * topographic findings of superior flattening and inferior steepening of the cornea * presence of Fleischer ring
Exclusion criteria
* history of prior ocular surgery (history of contact lens use is not an exclusion criterion) * average corneal power \> 60 D * presence of corneal scarring * corneal thickness 400 µ or less * history of herpes simplex virus keratitis * history of uveitis * pre-existing glaucoma
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Average corneal power of the cornea in the central 4 mm. | 24 months |
| Best corrected visual acuity | 24 months |
| Spherical equivalent power of the cornea (Best spectacle refraction) | 24 months |
| KMax: the maximum corneal curvature | 24 months |
Secondary
| Measure | Time frame |
|---|---|
| Corneal resistance factor. | 24 months |
| Maximal posterior surface elevation of the cornea. | 24 months |
| Apical corneal thickness. | 24 months |
| Endothelial count. | 24 months |
Countries
United States
Contacts
Primary ContactJames J. Reidy, M.D.
Backup ContactJeanne Stutz
Outcome results
None listed