title: Power Profiles and In Vitro Optical Quality of Scleral Contact Lenses: Effect of the Aperture and Power.
abstract: OBJECTIVE
  To assess the power profile and in vitro optical quality of scleral contact lenses with different powers as a function of the optical aperture.
  
  
  METHODS
  The mini and semiscleral contact lenses (Procornea) were measured for five powers per design. The NIMO TR-1504 (Lambda-X) was used to assess the power profile and Zernike coefficients of each contact lens. Ten measurements per lens were taken at 3- and 6-mm apertures. Furthermore, the optical quality of each lens was described in Zernike coefficients, modulation transfer function, and point spread function (PSF). A convolution of each lens PSF with an eye-chart image was also computed.
  
  
  RESULTS
  The optical power fluctuated less than 0.5 diopters (D) along the optical zone of each lens. However, the optical power obtained for some lenses did not match with its corresponding nominal one, the maximum difference being 0.5 D. In optical quality, small differences were obtained among all lenses within the same design. Although significant differences were obtained among lenses (P<0.05), these showed small impact in the image quality of each convolution.
  
  
  CONCLUSIONS
  Insignificant power fluctuations were obtained along the optical zone measured for each scleral lens. Additionally, the optical quality of both lenses has showed to be independent of the lens power within the same aperture.
authors.affiliation: Optometry Research Group (GIO), Department of Optics (A.D.-V., J.J.E.-T., A.R.), University of Valencia, Burjasot, Spain; and Unit of Optometry (R.B.), Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Alberto
authors.initials: A
authors.lastname: Domínguez-Vicent
authors.forename: Jose Juan
authors.initials: JJ
authors.lastname: Esteve-Taboada
authors.forename: Alberto
authors.initials: A
authors.lastname: Recchioni
authors.forename: Rune
authors.initials: R
authors.lastname: Brautaset
mesh_terms: D000704:Analysis of Variance; D003261:Contact Lenses / Q000592:standards*; D004867:Equipment Design; D006801:Humans; D066298:In Vitro Techniques; D055095:Optics and Photonics; D012029:Refraction, Ocular / Q000502:physiology*