Ethanol Preserved Cornea Donors As Long-Term Storage For Acute Tectonic Keratoplasties

Acute corneal perforation is a sight-threatening ocular emergency requiring immediate surgical closure. Globe restitution for defects too large for gluing or amniotic membrane transplantation require tectonic keratoplasty to provide sufficient biological tissue replacement. There is a global shortage of corneal tissue especially for emergency procedures. Ethanol preserved corneal tissue is devitalized, immunologically neutral, chemically crosslinked, and suitable for long-term preservation. This study examines the long-term outcome of ethanol stored corneoscleral tissue as a readily available corneal grafts for emergency tectonic keratoplasty.

The study was conducted as a monocentric, retrospective chart review at the Department of Ophthalmology of the Medical University of Innsbruck (MUI), Austria.

All consecutive patients who underwent tectonic keratoplasty for corneal perforation between January 2018 and December 2022 were included and reviewed. The MUI eye bank provides corneoscleral tissue unsuitable for keratoplasty due to low endothelial cell counts, stored in 95% ethanol. Prior to the procedure, it is thoroughly rinsed for 20 minutes and prepared by the surgeon to match the size of the defect. Demographic data and the underlying disease, as well as surgical data including information on graft size and specifics of the surgical technique were collected. The postoperative analysis focused on the durability of the graft (Intact Globe Restitution Interval).

21 emergencies tectonic procedures of 16 patients (6 female, 10 male) were included. Mean age was 79.5+/-12.3 years. The underlying ocular diseases were neurotrophic (38%), peripheral ulcerative (38%), metaherpetic (19%) and other infectious (5%) ulcers. The mean graft diameter was 4.2+/-1.2 mm (range 3-7mm). Mean intact globe restitution interval was 16.3 +/-14.6 months. Epithelial closure was observed after an average of 22.4+/-24 days. 12 cases did not need any further surgery whereas 9 cases received re-surgery for either visual rehabilitation (n=2), enucleation (n=1) or re-perforation (n=6, 29%) due to uncontrollable systemic disease. Final visual acuity was 1.6+/-0.8 logmar.

Ethanol stored donor corneal tissue is a feasible alternative to organ culture preserved tissue for emergency tectonic keratoplasty to close corneal perforations. Its use provided long term globe restitution and allowed subsequent elective penetrating keratoplasty for visual rehabilitation.