Long‐term clinical course of amniotic membrane after permanent amniotic membrane transplantation

Aims/Purpose: To investigate the long‐term clinical outcomes of transplanted amniotic membrane in patients who underwent permanent amniotic membrane transplantation (P‐AMT) on cornea. Methods: From April 2014 to March 2021, medical records and digital photographs of 68 patients (72 eyes) who underwent P‐AMT were analysed retrospectively. The duration of complete re‐epithelization of cornea and wearing therapeutic contact lens (T‐lens) after surgery were investigated, the size of preserved amniotic membrane (AM) excluding the melted portion was analysed using the Image J program every year up to 6 years after surgery, and it was compared by dividing into a single‐layer group and a double‐layer group. In addition, when the AM melts, the cause, time, and related factors of melting were analysed. Results: The average duration to complete re‐epithelialization after surgery was 12.2 ± 11.0 days, and T‐lens were worn on average up to 8.7 ± 8.5 months after surgery. In total group, the average ratio of preserved AM annually up to 6 years after surgery was 94.9%, 94.3%, 97.8%, 96.4%, 95.8%, 91.6% respectively, and there was no significant difference between the single‐layer group and the double‐layer group. AM melting appeared in 38.9% (28 eyes) of the total group, and melting was first observed on average 16.4 ± 17.2 months after surgery. The formation and rupture of bullae was the most common cause of melting at 71.4% (20 eyes), and there were no statistically significant related factors involved in the formation of bullae. Conclusions: In the case of P‐AMT performed in various diseases of the cornea, the transplanted AM is partially melt but considered to be well preserved up to 6 years after surgery to form a stable ocular surface.