Study of the Safety and Effectiveness of Collagen Cross-Linking at an Irradiance of 9 mW/cm2 and 18 mW/cm2

General Inclusion Criteria

Prospective subjects must meet all of the following criteria to be eligible for
participation:

- 18 years of age or older

- Signed written informed consent

- Willingness and ability to comply with schedule for follow-up visits

- Contact lens removal prior to evaluation and treatment

Inclusion criteria for progressive keratoconus

Prospective subjects must meet two of the following criteria:

- Having a diagnosis of progressive keratoconus:

- An increase of ≥ 1.00 D in the steepest keratometry value

- An increase of ≥ 1.00 D in astigmatism manifest refraction

- A myopic shift (decrease in the spherical equivalent) of ≥ 0.50 D on subjective
manifest refraction

- Presence of central or inferior steepening on the Pentacam map.

- Axial topography consistent with keratoconus

- Steepest keratometry (Kmax) value ≥ 47.00 D

Inclusion criteria for ectasia

Prospective subjects must meet the following criteria:

- History of having undergone a keratorefractive procedure

- Meeting two of the following criteria

- Steepening by topography, either Pentacam or Humphrey

- Thinning of cornea

- Shift in the position of thinnest portion of cornea

- Change in refraction with increasing myopia

- Development of myopic astigmatism

- Development of irregular astigmatism

- Loss of best spectacle corrected acuity. 6.2 Exclusion Criteria

Subjects meeting any of the following criteria will be excluded from this protocol:

- Eyes classified as either normal, atypical normal,

- Corneal pachymetry ≤ 350 microns at the thinnest point measured by Pentacam in the
eye to be treated

- A history of chemical injury or delayed epithelial healing in the eye to be treated.

- 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 treatment

- Inability to cooperate with diagnostic tests.

- Patients with a current condition that, in the investigator's opinion, would
interfere with or prolong epithelial healing.

- Taking Vitamin C (ascorbic acid) supplements within 1 week of the cross-linking
treatment.

- Patients who are unable to remain supine and tolerate a lid speculum for an extended
period of time.