This study study is to determine the effectiveness of cornea cross linking in patients with Keratoconus or other cornea thinning conditions.

This study is an investigator initiated single center study that will be conducted over 10 years. Up to 300 patients with cornea thinning conditions will be enrolled. This is a prospective, single-arm, nonrandomized single site study to determine the safety and effectiveness of the PXL Platinum 330 system for performing collagen cross linking (CXL) in eyes with cornea thinning. Subjects with a history of keratoconus, pellucid marginal degeneration, thin corneas undergoing LASIK, PRK or INTACS will be evaluated for suitability as a candidate for CXL. Subjects that are candidates for CXL will be asked to participate in this study and will undergo the required screening procedures to determine eligibility. Informed consent will be obtained from each subject before performing any study procedures.

Eyes undergoing CXL will have topical anesthetic administered and then have topical riboflavin instilled on the cornea for 25 minutes, followed by UVA light 9mW/cm2 for 10 minutes. The CXL procedures will be performed on an outpatient basis using the PXL Platinum 330 System (UVA light source with riboflavin solution). All use of the PXL Platinum 330 System will be in accordance with this protocol and the general instructions provided be the manufacturer in the PXL Platinum 330 operator's manual.

All subjects will be evaluated at screening/baseline, Day 0 (treatment day), 1 day, 1 week and 1,3,6 and 12 months after treatment. Topographic keratometry, posterior cornea measurements (with Pentacam), cornea topography, manifest refraction, and measurements of best spectacle corrected visual acuity and intraocular pressure will be obtained at baseline and appropriate times after the CXL treatment. Safety monitoring throughout the study will include observations for subjective complaints, complications, adverse events, clinically significant findings on ophthalmic examination, dilated fundus examination and slit-lamp examination. Quality of vision and subjective complaints will be evaluated preoperatively and postoperatively with a vision related quality of life questionnaire.

Inclusion Criteria:

• healthy subjects with no other medical or ocular conditions

Subjects who have one or both eyes that meet criteria 1 and 1 or more of the following criteria will be considered candidates for this study:

• 18 years of age or older

• Presence of central or inferior steepening (on Pentacam topograph)

• Axial topography consistent with keratoconus, post-surgical ectasia, or pellucid marginal degeneration (See keratoconus grading section 7.0 for details)

• Presence of one or more findings associated with keratoconus or pellucid marginal degeneration on slit lamp exam such as:

  • Fleischer ring
  • Vogt's striae
  • Decentered corneal apex
  • Munson's sign
  • Rizzutti's sign
  • Apical Corneal scarring consistent with Bowman's breaks
  • Scissoring of the retinoscopic reflex
  • Crab-claw appearance on topography

• Steepest keratometry (Kmax) value ≥ 47.20 D on simK or Pentacam

• I-S keratometry difference > 1.5 D on the Pentacam/Galilei/Orbscan/Cassini map or topography map

• Posterior corneal elevation >16 microns (µm on Pentacam tomography)

• Thinnest corneal point <485 microns (ultrasound pachymetry or Pentacam tomography)

• Predicted Post LASIK/PRK stromal ablation depth <350 microns or expected keratometry >47.2 D, or patients undergoing PRK/SMILE in keratoconus suspect eyes

• Bacterial or fungal corneal keratitis persistent and not responding despite > 2 weeks of standard antimicrobial therapy or with rapid progression of corneal thinning, with loss of >25% corneal thickness

• Contact Lens Wearers Only:

  • Removal of contact lenses for the required period of time prior to the screening refraction:

Contact Lens Type Minimum Discontinuation Time Soft 1 Week Soft Extended Wear 2 Weeks Soft Toric 3 Weeks Rigid gas permeable 2 Weeks per decade of wear

• Signed written informed consent
• Willingness and ability to comply with schedule for follow-up visits

Exclusion Criteria:

• active infections, collagen vascular disease, allergic to product

All subjects meeting any of the following criteria will be excluded from this study:

• Eyes classified as either normal or atypical normal on the severity grading scheme.

• Corneal pachymetry at the screening exam that is <300 microns at the thinnest point 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, for example:

  • History of or active corneal disease (e.g., herpes simplex, herpes zoster keratitis, recurrent erosion syndrome, acanthomeoeba, etc.)
  • Clinically significant corneal scarring in the CXL treatment zone that is not related to keratoconus or, in the investigator's opinion, will interfere with the cross-linking procedure.

• Pregnancy (including plan to become pregnant) or lactation during the course of the study

• A known sensitivity to study medications

• Patients with cognitive or ambulatory conditions that would prevent eye drop compliance with 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 physician's opinion, would interfere with or prolong epithelial healing.