title: Theoretical strategy for choosing piggyback intraocular lens powers in young children.
abstract: BACKGROUND
  The normal growth of a young child's pseudophakic eye can result in a large myopic shift. Temporary polypseudophakia using piggyback intraocular lenses (IOLs) has been proposed as a means to reduce the amount of myopic shift by removing the anterior IOL when the eye becomes sufficiently myopic. Since the rate of refractive growth can be used to predict the refractive curve over time in pseudophakic children, we used this knowledge to develop a theoretical strategy for choosing IOL power combinations for temporary polypseudophakia.
  
  
  METHODS
  We used a novel Pediatric Piggyback IOL Calculator to develop a strategy for choosing the powers of the anterior and posterior IOLs. We graphed the predicted results for several combinations of piggyback IOL powers and chose the combination of IOL powers that appeared to give the best results, based on the known rate of refractive growth (5.4 D) and its standard deviation (2.4 D). We aimed for a combination to minimize the hyperopic or myopic refractive error during the first 6 years of life to facilitate amblyopia management and minimize the refractive error at age 20 years.
  
  
  RESULTS
  We found optimal results when the initial postoperative goal refraction with polypseudophakia was moderate hyperopia and the anterior IOL had approximately 20% of the total required IOL power.
  
  
  CONCLUSIONS
  This theoretical strategy can be used to determine piggyback IOL powers to use in children.
authors.affiliation: The University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA.
authors.forename: Chantal
authors.initials: C
authors.lastname: Boisvert
authors.forename: David T
authors.initials: DT
authors.lastname: Beverly
authors.forename: Scott K
authors.initials: SK
authors.lastname: McClatchey
mesh_terms: D000293:Adolescent; D002387:Cataract Extraction; D002648:Child; D002675:Child, Preschool; D005123:Eye / Q000254:growth & development; D006801:Humans; D006956:Hyperopia / Q000503:physiopathology*; D007223:Infant; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008962:Models, Theoretical; D009216:Myopia / Q000503:physiopathology*; D055095:Optics and Photonics; D019591:Pseudophakia / Q000503:physiopathology*; D012029:Refraction, Ocular / Q000502:physiology; D055815:Young Adult