Treatment of Keratoconus Using Collagen Cross-Linking

University at Buffalo

Status and phase: Unknown; Phase 3; Phase 2

Conditions: Keratoconus

Treatments: Drug: Sham cross-linking; Drug: Riboflavin-5-phosphate

Study type: Interventional

Funder types: Other

Identifiers

NCT00841386

101365

Details and patient eligibility

About

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. .

Full 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.

Enrollment: 150 estimated patients

Sex: All

Ages: 16 to 35 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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150 participants in 2 patient groups

Cross-linking treatment

Experimental group

Description:

Topical anesthesia (lidocaine jelly 2%) will be used. The central 9 mm of corneal epithelium will be removed cautiously with an Amoils brush. Riboflavin 0.1% solution will be applied (10 mg riboflavin-5-phosphate in 10 ml dextran T-500 20% solution, supplied in a sterile, single dose container) to the cornea every 2-3 minutes for 15 minutes and then every 5 minutes thereafter. The UV source will be from the CBM VEGA X-linker (CSO, Florence, Italy). A wavelength of 370 nm will be used to direct 5.4 J/cm2 to the area of cornea debrided for 30 minutes. The distance from the UV source to the cornea will be 1.5 to 5.4 cm.

Treatment:

Drug: Riboflavin-5-phosphate

Sham treatment group

Sham Comparator group

Description:

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 a 2% methylcellulose solution combined with 1% fluorescein dye will be applied to the cornea every 5 minutes for 30 minutes. The patient will be placed under the UV device, but instead of the UV light, the LED aiming beam will be applied for 30 minutes.

Treatment:

Drug: Sham cross-linking