Evaluating a new system for cornea crosslinking in patients with cornea thinning

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.