Corneal Crosslinking in Patients With Keratoconus and Post-Refractive Ectasia

The primary objective of this study is to evaluate two riboflavin-dosing regimens for corneal collagen cross-linking to slow the progressive changes in corneal curvature in eyes with progressive keratoconus or post-refractive ectasia.

Inclusion criteria

• 10 years of age or older
• Having documented ectasia on topography or tomography after previous refractive surgery OR progressive keratoconus defined as one or more of the following changes over a period of 36 months or less before randomization:

• An increase of ≥ 1.00 D in the steepest keratometry value (or sim K)
• An increase of ≥ 1.00 D in regular astigmatism evaluated by subjective manifest refraction
• A myopic shift (decrease in the spherical equivalent) of ≥ 0.50 D on subjective manifest refraction
• Documented decrease in visual acuity associated with irregular astigmatism and topographic features of ectasia.
• Subjects with keratoconus diagnosis only:

a. Axial topography consistent with keratoconus b. Presence of central or inferior steepening on the Pentacam map. c. Presence of one or more slit lamp findings associated with keratoconus, such as: i. Fleischer ring ii. Vogt striae iii. Corneal thinning iv. Corneal scarring

• Contact Lens Wearers Only: Removal of contact lenses for the required period of time prior to the screening refraction:

Contact Lens Type Minimum Discontinuation Time Soft 3 Days Soft Extended Wear 1 Week Soft Toric 2 Weeks Rigid gas permeable 2 Weeks

• Signed written informed consent

Exclusion criteria

• 1. Any keratoconus patient over 21 years of age without evidence of progression of his corneal deformity.

• Patients with excessively thin corneas. 3. Previous ocular condition in the eyes to be treated that may predispose the eye for future complications, for example:

a. History of corneal disease (e.g., herpes simplex, herpes zoster keratitis, recurrent erosion syndrome, corneal melt, corneal dystrophy, etc.) b. Clinically significant corneal scarring in the proposed treatment zone 4. A history of chemical injury or delayed epithelial healing in the eye(s) to be treated.

• A known sensitivity to treatment medications. 6. Patients with a current condition that, in the treating physician's opinion, would interfere with or prolong epithelial healing.

• Pregnancy (including plan to become pregnant) or lactation during the course of the study