title: Two-year preclinical testing of perfluoropolyether polymer as a corneal inlay.
abstract: OBJECTIVE
  To assess the long-term biocompatibility and optical clarity of a perfluoropolyether (PFPE) polymer as a corneal inlay.
  
  
  METHODS
  A 4-mm-diameter PFPE inlay was implanted under a microkeratome flap in the corneas of rabbits (n = 16) and maintained for predetermined time points of 6, 12, or 24 months. These were compared with normal (n = 3) and time-matched sham-wounded rabbit corneas (n = 8). All corneas were monitored clinically with a slit lamp. Histology was performed on all eyes on termination to assess the tissue response.
  
  
  RESULTS
  Some sham and implanted animals were discontinued from study 1 to 2 days after surgery because of flap dislodgement. Ten animals with PFPE inlays remained in the study, and 7 of these were maintained to their predetermined time point for up to 2 years (3 were discontinued because of peripheral corneal defects). The corneas of these 7 animals remained clear and healthy, tear film remained normal, and there were no signs of inflammation, neovascularization, or increased conjunctival redness. All inlays remained centered and optically clear (clarity 85% or greater). Histology showed PFPE was biostable. The epithelia of operated corneas were stratified but slightly thinned compared with those of normal corneas. Stromal tissue anterior and posterior to each inlay appeared normal. Keratocytes in the vicinity of the inlay were normal in distribution but showed increased vacuolation, indicating tissue repair after the surgery.
  
  
  CONCLUSIONS
  The PFPE polymer maintained a high level of optical clarity and showed long-term biocompatibility for up to 2 years when implanted as an inlay in the rabbit cornea.
authors.affiliation: Vision Cooperative Research Centre, University of NSW, Sydney, Australia.
authors.forename: Ruo Zhong
authors.initials: RZ
authors.lastname: Xie
authors.forename: Margaret D M
authors.initials: MD
authors.lastname: Evans
authors.forename: Barbara
authors.initials: B
authors.lastname: Bojarski
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Hughes
authors.forename: Grace Y
authors.initials: GY
authors.lastname: Chan
authors.forename: Xuan
authors.initials: X
authors.lastname: Nguyen
authors.forename: John S
authors.initials: JS
authors.lastname: Wilkie
authors.forename: Keith M
authors.initials: KM
authors.lastname: McLean
authors.forename: Antti
authors.initials: A
authors.lastname: Vannas
authors.forename: Deborah F
authors.initials: DF
authors.lastname: Sweeney
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001672:Biocompatible Materials; D003315:Cornea / Q000502:physiology / Q000601:surgery* / Q000648:ultrastructure; D004353:Drug Evaluation, Preclinical; D004987:Ethers; D005353:Fibronectins / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D005466:Fluorocarbons; D008422:Materials Testing; D046529:Microscopy, Electron, Transmission; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D011817:Rabbits; D013524:Surgical Flaps; D013997:Time Factors
chemical_list: D000199:Actins; D001672:Biocompatible Materials; D004987:Ethers; D005353:Fibronectins; D005466:Fluorocarbons; C078113:perfluoropolyether