title: Toward New Engagement Paradigms For Intraocular Lenses: Light-Initiated Bonding of Capsular Bag to Lens Materials.
abstract: OBJECTIVE
  Successful intraocular lens procedures, that is, implantation of accommodating intraocular lenses (A-IOL), require firm engagement of the IOL haptics to the capsular bag. We evaluated the use of photochemical bonding to engage IOL materials to the capsular bag.
  
  
  METHODS
  Freshly enucleated eyes of New Zealand rabbits were used in two types of photobonding experiments using Rose Bengal (RB) photoinitiation and green light (532-nm) irradiation. First, RB-stained capsular bag strips were photobonded ex vivo to IOL polymer [poly(2-hydroxyethyl methacrylate) pHEMA] strips in an atmosphere of air and of nitrogen. Second, IOLs were implanted intracapsularly and photobonded intraocularly. Irradiation times were between 30 and 180 seconds, and laser irradiance was between 0.25 and 0.65 W/cm(2). The strength of the bonding was tested using a custom-developed uniaxial extensiometry system and the breakage load (the load that caused breakage per bonded area) was calculated.
  
  
  RESULTS
  The breakage load of ex vivo capsule-pHEMA bonds increased exponentially with irradiation time, using 0.45 W/cm(2). In air, the average breakage load across all conditions was 1 g/mm(2) and 1.6 times lower than that in a nitrogen atmosphere. Intraocularly, RB-stained IOLs were strongly photobonded to the capsule bag with breakage loads > 0.8 g/mm(2).
  
  
  CONCLUSIONS
  Breakage of the photobonded linkage between IOL material and capsular bag required loads substantially greater than the maximum force of ciliary muscle, suggesting that this technology may introduce a new paradigm for engagement of A-IOLs. The bonding produced in air was stronger than that in nitrogen atmosphere, suggesting that oxygen is involved in the chemical mechanism for photobonding.
authors.affiliation: Instituto de Óptica Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Marcos
authors.affiliation: Instituto de Óptica Consejo Superior de Investigaciones Científicas, Madrid, Spain 2Fundación Jiménez Díaz, Madrid, Spain.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Alejandre
authors.affiliation: Instituto de Óptica Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Lamela
authors.affiliation: Instituto de Óptica Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Dorronsoro
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Irene E
authors.initials: IE
authors.lastname: Kochevar
mesh_terms: D000818:Animals; D007903:Lens Capsule, Crystalline / Q000601:surgery*; D019654:Lens Implantation, Intraocular / Q000379:methods*; D007910:Lenses, Intraocular; D008027:Light; D008422:Materials Testing / Q000379:methods*; D008689:Methacrylates; D018918:Phacoemulsification; D010775:Photic Stimulation; D011474:Prosthesis Design; D011817:Rabbits
chemical_list: D008689:Methacrylates; C005044:hydroxyethyl methacrylate