Potential of Perfluoropolyether Polymer as a Corneal Inlay

Abstract

Abstract: : Purpose: To investigate biocompatibility and optical stability of perfluoropolyether (PFPE) -modified polymers as a potential corneal inlay. Methods: Sixteen New Zealand white rabbits ranging in age from 1 to 2 years were used in the study and were randomly divided to two groups: the implant- and sham-groups (n = 8 each). In the implant-group, a LASIK flap of 8 – 8.5 mm diameter and 100 – 120 µ m thickness was created in the central cornea and the flap rolled over to the nasal portion of the cornea. A PFPE inlay of 4 mm diameter was then placed onto the stromal bed and the flap rolled back to cover the inlay. Finally a soft contact lens was inserted to cover the flap. The sham-group underwent similar procedures except that no inlay was implanted. Eyes were monitored post- operatively with slit-lamp biomicroscopy twice weekly for optical clarity of the inlay and for any changes in the conjunctival and corneal responses and appearance (for example corneal infiltrates, oedema). At 6 months of implantation 5 animals (n = 3 implanted, n = 2 sham) were sacrificed and the eyes processed for histology under light and electron microscopy. Results: Post operative monitoring of the eyes up until 12 months demonstrated no adverse responses in both implant and sham groups. In the test eyes, the inlay continued to be located at the central cornea and remained optically clear and deposit-free. The epithelium and anterior and posterior stroma were clinically normal. Histology at the 6 month time point, showed no inflammatory response of the corneal tissue associated with the implanted polymer. The epithelium anterior to LASIK cut was stratified but thinned in both sham and implanted animals and was not fully healed. The stroma and the endothelium were normal. Conclusions: The results suggest that, PFPE polymer is optically stable and biocompatible and appears to be a potential candidate material for corneal inlays.

Keywords: cornea: clinical science • cornea: stroma and keratocytes • clinical research methodology