title: [Intraocular lens power calculation in complicated cases: the "Silguero"method].
abstract: OBJECTIVE
  To report a new method for intraocular lens (IOL) calculation in patients treated by corneal refractive surgery, in whom the application of other methods is not possible because of the absence of necessary data. This method is also applicable in other situations where the IOL calculation is difficult and in cases of IOL exchange because of unexpected refractive difficulties.
  
  
  METHODS
  We performed phaco-emulsifications, refracting the patient's eye before IOL implantation, using the refraction data in aphakia as the only variable for the application of the formula, which itself is based on the existing correlation between the graduation of glasses (12 mm) and the IOL power at the lens level. The formula has been applied in 3 patients in whom no other calculation method was applicable.
  
  
  RESULTS
  After the appropriate intervention, the 3 patients presented a spherical equivalent below 1 diopter.
  
  
  CONCLUSIONS
  We believe this formula is valid in some situations where other formulas cannot be applied because of the absence of the necessary variables.
authors.affiliation: Centro Insular de Oftalmología, Las Palmas de Gran Canaria, España. dpsilguero@msn.com
authors.forename: D
authors.initials: D
authors.lastname: Pérez-Silguero
authors.forename: M A
authors.initials: MA
authors.lastname: Pérez-Silguero
authors.forename: F R
authors.initials: FR
authors.lastname: Pérez-Hernández
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007910:Lenses, Intraocular; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D009885:Ophthalmology / Q000379:methods; D055095:Optics and Photonics