This randomized clinical trial will assess corneal astigmatism and visual outcomes in participants who have undergone corneal transplantation for keratoconus with ex vivo cross-linked donor corneal tissue versus participants who have undergone corneal transplantation for keratoconus with non-cross-linked donor corneas. Crosslinking is a procedure that stabilizes the biomechanical properties of the cornea; as a result, the cornea stiffens. It has been shown that this procedure stabilizes the cornea of patients with keratoconus or corneal ectasias. The FDA currently approves crosslinking for patients with progressive keratoconus and corneal ectasia following refractive surgery. Ex vivo crosslinking of donor corneal tissue for patients with keratoconus undergoing PK or DALK could stabilize the cornea and reduce the risk of high astigmatism and improve vision in patient with keratoconus.
The 15 clinical sites are expected to recruit cumulatively 216 cases over 18 months. Eligibility is assessed during a routine examination by an investigator. Informed consent will be obtained prior to collecting any information that is not part of usual care. Patients who meet all inclusion criteria and none of the exclusion criteria will be given the opportunity to participate in the study. Participants will be randomly assigned to the treatment group (cross-linked corneal tissue) or control group (non-cross-linked corneal tissue that has been exposed to riboflavin, but no ultraviolet light). The investigator will request a cadaveric cornea from the study's central eye bank CorneaGen, which will prepare the cadaveric cornea. Participants will receive the cross-linked donor tissue or control donor tissue during surgery. Clinical sites, including surgeons, and participants will be masked to treatment assignment. Participants will be followed up post-operatively by the site investigators as per the standard of care. This will include visits at 1 Day, 1 Week, 1 Month, 6 Months, 1 Year, 1.5 Years, 2 Years, and 2.5 Years post-surgery. Some participants may need to be seen more regularly for routine care. The investigators will monitor for systemic and ocular adverse events at all follow-up visits.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
216
A wavelength of 365 nm ultraviolet A light will be used to direct 5.4 J/cm2 using a beam diameter of 9.5mm to treat the de-epithelialized corneal surface of a donor cornea for 30 minutes. Every 2 minutes, the UV light will be used while another drop of riboflavin is applied on top of the donor cornea.
The corneal tissue for the control arm will be treated the same as the crosslinked tissue except that it will not be exposed to ultraviolet light. The donor cornea will be placed on an artificial anterior chamber maintainer and the epithelium will be removed mechanically. Riboflavin solution (0.1% riboflavin and 20% dextran supplied in a sterile, single-dose container) will be applied to the cornea every 2 minutes for 30 minutes.
Massachusetts Eye and Ear Infirmary
Boston, Massachusetts, United States
• Keratometric astigmatism with Pentacam Schiempflug imaging at 130 weeks post-surgery.
• Keratometric astigmatism with Pentacam Schiempflug imaging at 130 weeks post-surgery
Time frame: 130 weeks
• Best spectacle corrected visual acuity (BSCVA) with ETDRS methodology at 2.5 years (130 weeks) post-surgery
• Best spectacle corrected visual acuity (BSCVA) with ETDRS methodology at 2.5 years (130 weeks) post-surgery
Time frame: 130 weeks
Manifest cylinder astigmatism at 130 weeks post-surgery
Manifest cylinder astigmatism at 130 weeks post-surgerykeratometry, anterior mean keratometry, posterior mean keratometry
Time frame: 130 weeks
Uncorrected visual acuity (UCVA) 130 weeks post-surgery
Uncorrected visual acuity (UCVA) 130 weeks post-surgery
Time frame: 130 weeks
Low-contrast BSCVA with ETDRS methodology at 130 weeks post-surgery
Low-contrast BSCVA with ETDRS methodology at 130 weeks post-surgerypermeable contact lens.
Time frame: 130 weeks
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