Corneal Sensitivity Cross-linking Keratoconus

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.

Eligibility Criteria:
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