Study of the Safety and Effectiveness of Photochemically Induced Collagen Cross-Linking in Eyes With Keratoconus.

INCLUSION CRITERIA GENERAL: 1. 12 years of age or older 2. Signed written informed consent 3. Willingness and ability to comply with schedule for follow-up visits 4. Contact lens removal prior to evaluation and treatment 5. Candidates must also have two of the following criteria: 1. Presence of central or inferior steepening on the Pentacam or Orbscan map consistent with Keratoconus. 2. Axial topography consistent with keratoconus. 3. Steepest keratometry (Kmax) value of 47.00D INCLUSION CRITERIA FOR ECTASIA: History of having undergone a keratorefractive procedure and 2 of the following criteria: 1. Steepening by topography, either Pentacam or Orbscan 2. Thinning of cornea 3. Shift in the position of thinnest portion of cornea 4. Change in refraction with increasing myopia 5. Development of myopic astigmatism 6. Development of irregular astigmatism 7. Loss of BSCVA EXCLUSION CRITERIA: I. Eyes classified as either normal or atypical normal 2. Corneal pachymetry 350 microns at the thinnest point measured by Pentacam in the eye to be treated 3. A history of chemical injury or delayed epithelial healing in the eye to be treated. 4\. Pregnancy (including plan to become pregnant) or lactation during the course of the study 5. A known sensitivity to study medications 6. Patients with nystagmus or any other condition that would prevent a steady gaze during the treatment 7. Inability to cooperate with diagnostic tests. 8. Patients with a concomitant condition that, in the investigator's opinion, would interfere with or prolong epithelial healing. 9\. Taking Vitamin C (ascorbic acid) supplements within 1 week of the cross-linking treatment. 10\. Patients who are unable to remain supine and tolerate a lid speculum for an extended period of time. \-