ExCrossV Multi Site Trial for Vascularized High Risk Keratoplasty

The main objective of this study is to determine the safety of Ex Vivo Cross Linking (CXL) of donor corneal tissue in participants who have undergone high-risk penetrating keratoplasty.

This is a randomized, double-masked, multi site clinical trial to determine the safety of Ex Vivo CXL of donor corneal tissue in 96 participants who have undergone high-risk penetrating keratoplasty. Participants will be randomized to receive either a corneal tissue that has been untreated vs. a corneal tissue that has been treated with Photrexa® Viscous \& Photrexa® and UV light. The tissue will be prepared by a Corneal Tissue Bank under Current-Good-Tissue-Practice (CGTP) and delivered to the respective institutions for transplantation. Participants will be monitored up to 24 months post-transplantation to assess for adverse events of the randomized tissue.

Inclusion Criteria: * Age 18 and older * Willing and able to provide written informed consent * Willing and able to comply with study assessments for the full duration of the study * Patients undergoing high-risk penetrating keratoplasty, defined as corneal neovascularization (NV) in 1 or more quadrants ≥2 mm from the limbus or extension of corneal NV to the graft-host junction in a previously failed graft * Superficial vessels are defined as those within the anterior one-third of the cornea and deep vessels within the posterior two-thirds of the cornea (i.e., deep stroma). Superficial CNV involving ≤2 quadrants (equivalent to ≤6 clock hours) without deep CNV are classified as mild. CNV with \>2 quadrants of superficial vessels (\>6 clock hours) or 1 quadrant of deep vessels (\>3 clock hours) as severe (36). Exclusion Criteria: * History of Stevens-Johnson syndrome or ocular pemphigoid * Ocular or periocular malignancy * Non-healing epithelial defect of at least 0.5x0.5 mm in host corneal bed lasting ≥6 weeks preoperatively * Uncontrolled glaucoma * Change in topical corticosteroid regimen within 14 days of transplantation * Use of systemic immunosuppressive for indication other than corneal graft rejection * Participation in another simultaneous medical investigation or trial * Pregnancy (positive pregnancy test) or lactating * Pre-menopausal women not using adequate contraception (Reliable intrauterine devices, hormonal contraception or a spermicide in combination with a barrier method) * Ocular infection within 30 days prior to study entry. * Presence of anterior chamber intraocular lens * Active uveitis within 90 days prior to the study entry. * No ocular surgery or procedure within 90 days prior to the study entry or concomitant to the study procedure.