To evaluate corneal sensitivity changes following corneal cross-linking (CXL) in patients with progressive lower stage keratoconus.

Thirty eight eyes of 19 patients (11 women, 8 men) were included in a prospective, nonrandomized clinical study. Mean patient age was 22 years (range, 18-26 years). Inclusion criteria were low stage bilateral progressive keratoconus, transparent cornea and thinnest corneal thickness ≥ 440 µm. Using the Cochet-Bonnet esthesiometer central corneal sensitivity was measured preoperatively, after 7 days, and once a month after surgery until recovery of the baseline preoperative level. Normal levels of central corneal sensitivity were considered above 40mm.

Inclusion Criteria:

• Be at least 18 years of age
• Provide written consent and sign a HIPAA form
• Willingness and ability to follow all instructions and comply with schedule for follow-up visits
• For females capable of becoming pregnant,agreet o have uurine pregnancy testing performed prior to treatment; must not be lactating, and must agree to use a medically acceptable form of birth control for at least one week prior to the treatment and continue to use the method until 1 month after the last dose of investigational product.
• Having topographic evidence of keratoconus which is graded as lower stage progressive keratoconus
• Presence of central or inferior steepening on the Pentacam map
• Steepest keratometry (Kmax) value greater than or equal to 51.00D
• BSCVA of 80 letters or fewer for keratoconus on ETDRS chart
• Contact lens wearers only: remove contact lenses one week prior to the screening refraction
• Contact lens wearers only: manifest refraction must be stable between two visits that occur at least 7 days apart

Exclusion Criteria:

• Contraindications, sensitivity or known allergy to the use of the test articles(S) or their components
• If female, be pregnant, nursing, or planning a pregnancy or have a positive urine pregnancy test at Visit 2 prior to treatment or during the course of the study
• Eyes classified as either normal,atypical normal,keratoconus suspect or mild keratoconus on the severity grading scheme
• A history of the insertion of INTACS in the eye to be treated
• A history of previous limbal relaxing incision procedure in the eye to be treated
• Corneal pachymetry that is <350 microns at the thinnest point measured by Pentacam in the eye to be treated
• Eyes which are aphakic
• Eyes which are pseudophakic and do not have a UV blocking lens implanted
• Previous ocular condition (other than refractive error) in the eye to be treated that may predispose the eye for future complications.
• A history of delayed epithelial healing in the eye to be treated
• Patients with nystagmus or any other condition that would prevent a steady gaze during the treatment or other diagnostic tests
• Patients with a currnet 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 crosslinking treatment
• A history of previous corneal crosslinking treatment in the eye to be treated
• Have used an investigational drug or device within 30 days of the study or be concurrently enrolled in another investigational drug or device study within 30 days of the study