title: Synchrony dual-optic accommodating intraocular lens. Part 1: optical and biomechanical principles and design considerations.
abstract: OBJECTIVE
  To describe a dual-optic accommodating intraocular lens (IOL) based on theoretical considerations.
  
  
  METHODS
  University and independent research group.
  
  
  METHODS
  Ray-tracing analysis using optical modeling software (ZEMAXTM, Focus Software Inc., Tucson, Ariz) in a theoretical model eye was used to analyze lens configurations to optimize the accommodative and magnification effects of axial lens displacement. Finite-element modelling using a commercially available PC-based software package (COSMOS DesignSTAR) was applied to design the biomechanical parameters of the inter-optic articulations and optics.
  
  
  RESULTS
  Ray-tracing analysis indicated that a dual-optic design with a high plus-powered front optic coupled to a minus posterior optic produced greater change in conjugation power of the eye compared to a single-optic intraocular lens and that magnification effects were unlikely to account for improved near vision. Finite-element modelling indicated that the 2 optics can be linked by spring-loaded haptics that allow anterior and posterior axial displacement of the front optic in response to changes in ciliary body tone and capsular tension.
  
  
  CONCLUSIONS
  A dual-optic design linked by spring haptics increases the accommodative effect of axial optic displacement with minimal magnification effect and has promise for improving the performance of accommodative intraocular lenses.
authors.affiliation: Department of Ophthalmology, University of California San Francisco, San Francisco, California, USA. mcleods@vision.ucsf.edu
authors.forename: Stephen D
authors.initials: SD
authors.lastname: McLeod
authors.forename: Luis G
authors.initials: LG
authors.lastname: Vargas
authors.forename: Val
authors.initials: V
authors.lastname: Portney
authors.forename: Albert
authors.initials: A
authors.lastname: Ting
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D001696:Biomechanical Phenomena; D002387:Cataract Extraction; D003198:Computer Simulation; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008433:Mathematics; D008962:Models, Theoretical; D055095:Optics and Photonics; D011474:Prosthesis Design; D012029:Refraction, Ocular / Q000502:physiology