Healing characteristics of acellular porcine corneal stroma following therapeutic keratoplasty

BACKGROUND: Acellular porcine corneal stroma (APCS) has proven to be a promising alternative to traditional corneal grafts. This prospective case series was conducted to further investigate the healing characteristics of APCS following keratoplasty. METHODS: Twenty-seven patients undergoing APCS implantation to treat infectious keratitis were included. The patients were followed up for 12 months after surgery. The main outcome measures included visual acuity, corneal transparency, graft thickness, and cellular and nerve regeneration. RESULTS: In the operated eyes, the best-corrected visual acuity (BCVA, in logarithm of the minimal angle of resolution [logMAR] units) increased from 1.23 ± 0.95 logMAR before surgery to 0.23 ± 0.18 logMAR at 12 months after surgery (P < .001). The contrast sensitivity was still evidently reduced, especially at higher spatial frequencies. Gradual transparency improvement was observed in APCS grafts post-operatively. After implantation, the APCS graft thickness initially increased (day 1 = 592.41 ± 52.69 µm) but then continuously decreased until 3 months after surgery (1 month = 449.26 ± 50.38 µm; 3 months = 359.63 ± 34.14 µm, P < .001). Graft reepithelialization was completed within 1 week. In the in vivo confocal microscopy scans, host keratocytes began to repopulate the APCS grafts between 3 and 6 months post-operatively; subbasal nerve regeneration was only noted in 18.52% (5/27) of the eyes by 12 months after surgery. CONCLUSIONS: Acellular porcine corneal stroma functions as an effective alternative to human corneal tissue in lamellar keratoplasty. However, APCS is somewhat different from fresh human cornea in term of the post-operative healing process, which warrants the attention of both clinicians and patients.