Corneal Collagen Crosslinking for Keratoconus and Ectasia Using Riboflavin/Dextran or Riboflavin/Methylcellulose

Inclusion Criteria:

• 12 years of age or older
• Having a diagnosis of keratoconus or corneal ectasia after corneal refractive surgery
• Presence of central or inferior steepening on the Pentacam map
• Axial topography consistent with keratoconus or post-surgical corneal ectasia
• Contact lens wearers only: removal of contact lens for the required period of 1 weekprior to the screening refraction
• Signed written informed consent
• Willingness and ability to comply with schedule for follow-up visits

Exclusion Criteria:

• Eyes classified as either normal, atypical normal, or keratoconus suspect on theseverity grading scheme
• Corneal pachymetry less than or equal to 300 microns at the thinnest point measured byPentacam in the eye(s) to be treated
• Previous ocular condition (other than refractive error) in the eye(s) to be treatedthat may predispose the eye for future complications, for example: History of cornealdisease (e.g., herpes simplex, herpes zoster keratitis, recurrent erosion syndrome,corneal melt, corneal dystrophy, etc.) Clinically significant corneal scarring in theCXL treatment zone
• A history of chemical injury or delayed epithelial healing in the eye(s) to be treated
• Pregnancy (including plan to become pregnant) or lactation during the course of thestudy
• A known sensitivity to study medications
• Patients with nystagmus or any other condition that would prevent a steady gaze duringthe CXL treatment or other diagnostic tests
• Patients with a current condition that, in the investigator's opinion, would interferewith or prolong epithelial healing