Keratin films for ocular surface reconstruction: Wound healing in an in-vivo model

The most commonly used tissue substitute for ocular surface reconstruction is human amniotic membrane (AM). Because of its low biomechanical strength and intransparency there is a need to search for alternatives of consistent quality. This study, further explored the biocompatibility of Keratin Film (KF) and its ability to sustain corneal epithelial wound healing. In three equal groups of 5 New Zeeland white rabbits a 4 mm superficial keratectomy was created in the right eye. Five eyes received a KF, five a human AM graft and the remaining five no implant. All eyes were treated with ofloxacin and dexamethasone eye drops and followed up for 10 days. Corneal fluorescein staining, vascularization, and transparency were assessed using slit lamp biomicroscopy according to a standardized grading score during and at the end of follow-up. The corneal-scleral-button was excised and processed for histology. After 10 days all eyes which had received a KF showed complete epithelial healing and no signs of neovascularization. In the AM group 1 eye showed a persistent epithelial defect at day 10 and 2 eyes showed neovascularization at day 7 resolving at day 10. Transparency improved progressively both in the KF group as well as in the AM group towards the end of the follow. Histology showed a multilayer epithelium firmly adherent to the KF with no evidence of keratocyte migration or inflammatory reaction in the corneal stroma. In this study on rabbit eyes KF better supported corneal epithelial wound healing than amniotic membrane.