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.