Study was terminated due to enrollment and other challenges attributable to the Covid-19 public health emergency.

To evaluate the safety and effectiveness of the PXL Platinum 330 device for performing Corneal Crosslinking in patients with corneal thinning conditions.

Patients with progressive keratoconus, pellucid marginal degeneration, or at risk for post-refractive corneal ectasia will be recruited and undergo epithelial-on corneal crosslinking with the Peschke PXL-330 system using pulsed, accelerated energy delivery. Patients will undergo monitoring for 1 year, with serial measurements of corneal topography, visual acuity, intraocular pressure and visual function questionnaire assessments.

Inclusion Criteria:

• Inclusion Criteria: Criterion 1,2,3 are required for all participants. Participants must also meet one or more of criteria 4-12 . Criterion 13 is relevant only for contact lens wearers

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

1. 12 years of age or older

2. Presence of central or inferior steepening.

3. Axial topography consistent with keratoconus, post-surgical ectasia, or pellucid marginal degeneration

4. Presence of one or more findings associated with keratoconus or pellucid marginal degeneration, such as:

   1. Fleischer ring
   2. Vogt's striae
   3. Decentered corneal apex
   4. Munson's sign
   5. Rizzutti's sign
   6. Apical Corneal scarring consistent with Bowman's breaks
   7. Scissoring of the retinoscopic reflex
   8. Crab-claw appearance on topography

5. Steepest keratometry (Kmax) value ≥ 47.20 D

6. I-S keratometry difference > 1.5 D on the Pentacam map

7. Posterior corneal elevation >16 microns

8. Thinnest corneal point <485 microns

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

10. Contact Lens Wearers Only:

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

11. Signed written informed consent

12. Willingness and ability to comply with schedule for follow-up visits

13. Contact Lens Wearers Only:

    1. 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

Exclusion Criteria (any of the following are reasons for exclusion):

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

2. Corneal pachymetry at the screening exam that is <300 microns at the thinnest point in the eye(s) to be treated.

3. Previous ocular condition (other than refractive error) in the eye(s) to be treated that may predispose the eye for future complications, for example:

   1. History of or active corneal disease (e.g., herpes simplex, herpes zoster keratitis, recurrent erosion syndrome, acanthamoeba, etc.)
   2. 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.

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

5. A known sensitivity to study medications

6. Patients with nystagmus or any other condition that would prevent a steady gaze during the CXL treatment or other diagnostic tests.

7. Patients with a current condition that, in the physician's opinion, would interfere with or prolong epithelial healing

   -

Patients recruited at a single center based on physician examination for corneal ectasia in one or both eyes. The first patient was screened for enrollment in June 2020, while the last patient was screened in October 2021.

1 year

Randomized at outset