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

The objective of this study is to investigate the difference between the two riboflavin
preparations during UV (ultraviolet) administration. Both riboflavin preparations currently
are in general use worldwide and in U.S. clinical trials of corneal collagen crosslinking.
The first preparation contains riboflavin in a dextran solution, which may tend to dehydrate
the cornea and keep it thinner. The second preparation contains riboflavin in a solution
without dextran; in this case, the relative hypotonicity may tend to keep the cornea better
hydrated and thicker. The primary goal of the study is to see if the use of hypotonic
riboflavin (rather than riboflavin with dextran) better maintains consistent corneal
thickness during the CXL procedure. The second goal of the study is to determine if better
maintenance of corneal thickness potentially could have benefits of better consistency of the
procedure, decrease in corneal haze formation, and improved safety of the endothelial cells.
Safety and efficacy outcomes will then be compared between the groups. In particular, we will
compare the corneal thickness measured by ultrasonic pachymetry immediately after the CXL
procedure in the randomized eyes. Secondary outcomes will include visual acuity, longer term
corneal thickness changes, and corneal steepness changes. Safety assessments will include a
tabulation of adverse events, patient symptoms, loss of visual acuity, changes in endothelial
cell density, slit lamp examination of the cornea and lens, and contact lens tolerance for
contact lens wearers

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.