Corneal Collagen Crosslinking for Progressive Keratoconus and Ectasia Using Riboflavin/Dextran and Hypotonic Riboflavin

Inclusion Criteria: * 18 years of age or older * A diagnosis of progressive keratoconus over a period of 24 months or less before randomization or a diagnosis of corneal ectasia after corneal refractive surgery * Vision with contact lenses or glasses is worse than 20/20 * Corneal thickness greater than 300 microns at the thinnest point Exclusion Criteria: * Eyes classified as either normal, atypical normal, or keratoconus suspect on the severity grading scheme. * Corneal pachymetry ≤ 300 microns at the thinnest point measured by Pentacam in the eye(s) to be treated. * Previous ocular condition (other than refractive error) in the eye(s) to be treated that may predispose the eye for future complications * Clinically significant corneal scarring in the CXL treatment zone * Pregnancy (including plan to become pregnant) or lactation during the course of the study * A known sensitivity to study medications * Patients with nystagmus or any other condition that would prevent a steady gaze during the CXL treatment or other diagnostic tests. * Patients with a current condition that, in the investigator's opinion, would interfere with or prolong epithelial healing.