title: Development of a Magnetic Attachment Method for Bionic Eye Applications.
abstract: Successful visual prostheses require stable, long-term attachment. Epiretinal prostheses, in particular, require attachment methods to fix the prosthesis onto the retina. The most common method is fixation with a retinal tack; however, tacks cause retinal trauma, and surgical proficiency is important to ensure optimal placement of the prosthesis near the macula. Accordingly, alternate attachment methods are required. In this study, we detail a novel method of magnetic attachment for an epiretinal prosthesis using two prostheses components positioned on opposing sides of the retina. The magnetic attachment technique was piloted in a feline animal model (chronic, nonrecovery implantation). We also detail a new method to reliably control the magnet coupling force using heat. It was found that the force exerted upon the tissue that separates the two components could be minimized as the measured force is proportionately smaller at the working distance. We thus detail, for the first time, a surgical method using customized magnets to position and affix an epiretinal prosthesis on the retina. The position of the epiretinal prosthesis is reliable, and its location on the retina is accurately controlled by the placement of a secondary magnet in the suprachoroidal location. The electrode position above the retina is less than 50 microns at the center of the device, although there were pressure points seen at the two edges due to curvature misalignment. The degree of retinal compression found in this study was unacceptably high; nevertheless, the normal structure of the retina remained intact under the electrodes.
authors.affiliation: School of Physics, University of Melbourne, Melbourne, Victoria, Australia.|School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Victoria, Australia.
authors.forename: Kate
authors.initials: K
authors.lastname: Fox
authors.affiliation: Department of Electrical and Electronic Engineering, University of Melbourne, Melbourne, Victoria, Australia.|National Vision Research Institute, Australian College of Optometry, Melbourne, Victoria, Australia.
authors.forename: Hamish
authors.initials: H
authors.lastname: Meffin
authors.affiliation: The Bionics Institute, Melbourne, Victoria, Australia.
authors.forename: Owen
authors.initials: O
authors.lastname: Burns
authors.affiliation: Centre for Eye Research Australia (CERA) Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.
authors.forename: Carla J
authors.initials: CJ
authors.lastname: Abbott
authors.affiliation: Centre for Eye Research Australia (CERA) Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.
authors.forename: Penelope J
authors.initials: PJ
authors.lastname: Allen
authors.affiliation: Centre for Eye Research Australia (CERA) Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.
authors.forename: Nicholas L
authors.initials: NL
authors.lastname: Opie
authors.affiliation: The Bionics Institute, Melbourne, Victoria, Australia.
authors.forename: Ceara
authors.initials: C
authors.lastname: McGowan
authors.affiliation: Centre for Eye Research Australia (CERA) Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Yeoh
authors.affiliation: School of Physics, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Arman
authors.initials: A
authors.lastname: Ahnood
authors.affiliation: Centre for Eye Research Australia (CERA) Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.
authors.forename: Chi D
authors.initials: CD
authors.lastname: Luu
authors.affiliation: School of Physics, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Rosemary
authors.initials: R
authors.lastname: Cicione
authors.affiliation: The Bionics Institute, Melbourne, Victoria, Australia.
authors.forename: Alexia L
authors.initials: AL
authors.lastname: Saunders
authors.affiliation: The Bionics Institute, Melbourne, Victoria, Australia.
authors.forename: Michelle
authors.initials: M
authors.lastname: McPhedran
authors.affiliation: The Bionics Institute, Melbourne, Victoria, Australia.
authors.forename: Lisa
authors.initials: L
authors.lastname: Cardamone
authors.affiliation: The Bionics Institute, Melbourne, Victoria, Australia.
authors.forename: Joel
authors.initials: J
authors.lastname: Villalobos
authors.affiliation: School of Physics, University of Melbourne, Melbourne, Victoria, Australia.|The Bionics Institute, Melbourne, Victoria, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Garrett
authors.affiliation: The Bionics Institute, Melbourne, Victoria, Australia.
authors.forename: David A X
authors.initials: DA
authors.lastname: Nayagam
authors.affiliation: School of Physics, University of Melbourne, Melbourne, Victoria, Australia.|The Bionics Institute, Melbourne, Victoria, Australia.
authors.forename: Nicholas V
authors.initials: NV
authors.lastname: Apollo
authors.affiliation: School of Physics, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Kumaravelu
authors.initials: K
authors.lastname: Ganesan
authors.affiliation: The Bionics Institute, Melbourne, Victoria, Australia.
authors.forename: Mohit N
authors.initials: MN
authors.lastname: Shivdasani
authors.affiliation: School of Physics, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Alastair
authors.initials: A
authors.lastname: Stacey
authors.affiliation: School of Physics, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Escudie
authors.affiliation: School of Physics, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Samantha
authors.initials: S
authors.lastname: Lichter
authors.affiliation: The Bionics Institute, Melbourne, Victoria, Australia.
authors.forename: Robert K
authors.initials: RK
authors.lastname: Shepherd
authors.affiliation: School of Physics, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Steven
authors.initials: S
authors.lastname: Prawer
mesh_terms: D000818:Animals; D002415:Cats; D004567:Electrodes, Implanted; D006358:Hot Temperature; D008280:Magnetics / Q000379:methods; D059346:Magnets / Q000737:chemistry*; D011474:Prosthesis Design; D019919:Prosthesis Implantation / Q000379:methods*; D012160:Retina / Q000601:surgery* / Q000648:ultrastructure; D057488:Visual Prosthesis / Q000737:chemistry*
keywords: Attachment; Bionic eye; Magnet; Retina