title: Remote manipulation of posterior lamellar corneal grafts using a magnetic field.
abstract: OBJECTIVE
  In posterior lamellar keratoplasty procedures such as Descemet stripping endothelial keratoplasty and Descemet membrane endothelial keratoplasty, the lamellar graft is manipulated directly or by injecting an air bubble. This preliminary study sought to evaluate the feasibility of guiding lamellar corneal grafts by generating a magnetic field.
  
  
  METHODS
  Rabbit and porcine Descemet stripping endothelial keratoplasty and Descemet membrane endothelial keratoplasty grafts were manually produced and immersed in a ferromagnetic solution containing nanomagnetic particles conjugated to streptavidin or in gadoteric acid. For the feasibility study, grafts were transferred to an artificial anterior chamber or plastic test tube and a magnetic field was generated with a handheld NdFeB disc magnet. The presence and the sustainability of graft motion were documented under various conditions. For the semiquantitative study, whole or partial grafts were transferred to a plastic test tube after immersion, and the amount of tissue retraction induced by the remote magnet was graded.
  
  
  RESULTS
  The grafts were successfully manipulated in all directions by the magnet, from a distance of up to 7 mm. They remained ferromagnetic more than 24 hours after immersion in the ferromagnetic solutions. The degree of retraction was affected by graft size, immersion time, time from immersion, and immersion solution.
  
  
  CONCLUSIONS
  Posterior lamellar corneal grafts may be made ferromagnetic and remotely manipulated by creation of a magnetic field. The ferromagnetic properties are adjustable. This technique holds promise in attaching and repositioning grafts during keratoplasty. Further research is needed to assess the possible effects of ferromagnetic solutions on corneal endothelial cells and on lamellar graft clarity.
authors.affiliation: Department of Ophthalmology, Rabin Medical Center, Petah Tikva, Israel. yoav.nahum@gmail.com
authors.forename: Yoav
authors.initials: Y
authors.lastname: Nahum
authors.forename: Tilda
authors.initials: T
authors.lastname: Barliya
authors.forename: Irit
authors.initials: I
authors.lastname: Bahar
authors.forename: Tami
authors.initials: T
authors.lastname: Livnat
authors.forename: Yael
authors.initials: Y
authors.lastname: Nisgav
authors.forename: Dov
authors.initials: D
authors.lastname: Weinberger
mesh_terms: D000818:Animals; D003287:Contrast Media; D057111:Descemet Stripping Endothelial Keratoplasty; D004728:Endothelium, Corneal / Q000502:physiology*; D060526:Magnetic Fields; D060328:Magnetic Phenomena; D008280:Magnetics / Q000295:instrumentation*; D059346:Magnets; D008536:Meglumine; D009942:Organometallic Compounds; D011817:Rabbits; D013552:Swine
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine