title: Indentation and needle insertion properties of the human eye.
abstract: OBJECTIVE
  Characterization of the biomechanical properties of the human eye has a number of potential utilities. One novel purpose is to provide the basis for development of suitable tissue-mimicking material. The purpose of this study was to determine the indentation and needle insertion characteristics on human eye globes and tissue strips.
  
  
  METHODS
  An indenter assessed the elastic response of human eye globes and tissue strips under increasing compressive loads. Needle insertion determined the force (N) needed to penetrate various areas of the eye wall.
  
  
  RESULTS
  The results demonstrated that globes underwent slightly greater indentation at the midline than at the central cornea, and corneal strips indented twofold more than scleral strips, although neither difference was significant (P=0.400 and P=0.100, respectively). Significant differences were observed among various areas of needle insertion (P<0.001). Needle insertion through the anterior sclera (adjacent to the limbus) and posterior sclera (adjacent to the optic nerve) required the greatest amount of force (0.954 and 1.005 N, respectively). The force required to penetrate the central cornea (0.518 N) was significantly lower than all other areas except the midline sclera (0.700 N) CONCLUSION: These data form the basis for further research into the development of a tissue-mimicking human eye construct with potential utility as a model for use in ophthalmology research and surgical teaching.
authors.affiliation: Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Matthews
authors.affiliation: Department of Ophthalmology and Pathology, Ivey Eye Institute, London, Ontario, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Hutnik
authors.affiliation: Department of Biology, Faculty of Science, Western University, London, Ontario, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Hill
authors.affiliation: Department of Civil and Environmental Engineering, Geotechnical Research Centre, Western University, London, Ontario, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Newson
authors.affiliation: Department of Ophthalmology and Vision Sciences, University of Toronto, Mississauga, Ontario, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Chan
authors.affiliation: Medical Devices, National Research Council Canada, London, Ontario, Canada.
authors.forename: G
authors.initials: G
authors.lastname: Campbell
mesh_terms: D000368:Aged; D003315:Cornea / Q000502:physiology*; D004548:Elasticity / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009339:Needles; D009799:Ocular Physiological Phenomena; D018583:Pliability / Q000502:physiology*; D011312:Pressure; D011677:Punctures; D012590:Sclera / Q000502:physiology*; D014019:Tissue Donors