title: Efficacy of a gas permeable contact lens to induce peripheral myopic defocus.
abstract: OBJECTIVE
  The purpose of this work was to evaluate the potential of a novel custom-designed rigid gas permeable (RGP) contact lens to modify the relative peripheral refractive error in a sample of myopic patients.
  
  
  METHODS
  Fifty-two right eyes of 52 myopic patients (mean [±SD] age, 21 [±2] years) with spherical refractive errors ranging from -0.75 to -8.00 diopters (D) and refractive astigmatism of 1.00 D or less were fitted with a novel experimental RGP (ExpRGP) lens designed to create myopic defocus in the peripheral retina. A standard RGP (StdRGP) lens was used as a control in the same eye. The relative peripheral refractive error was measured without the lens and with each of two lenses (StdRGP and ExpRGP) using an open-field autorefractometer from 30 degrees nasal to 30 degrees temporal, in 5-degree steps. The effectiveness of the lens design was evaluated as the amount of relative peripheral refractive error difference induced by the ExpRGP compared with no lens and with StdRGP conditions at 30 degrees in the nasal and temporal (averaged) peripheral visual fields.
  
  
  RESULTS
  Experimental RGP lens induced a significant change in relative peripheral refractive error compared with the no-lens condition (baseline), beyond the 10 degrees of eccentricity to the nasal and temporal side of the visual field (p < 0.05). The maximum effect was achieved at 30 degrees. Wearing the ExpRGP lens, 60% of the eyes had peripheral myopia exceeding -1.00 D, whereas none of the eyes presented with this feature at baseline. There was no significant correlation (r = 0.04; p = 0.756) between the degree of myopia induced at 30 degrees of eccentricity of the visual field with the ExpRGP lens and the baseline refractive error.
  
  
  CONCLUSIONS
  Custom-designed RGP contact lenses can generate a significant degree of relative peripheral myopia in myopic patients regardless of their baseline spherical equivalent refractive error.
authors: *OD, MSc †OD, PhD ‡OD, PhD, FIACLE Centro Médico Teknon, Barcelona, Spain (JP); Clinical and Experimental Optometry Research Lab (CEORLab), Center of Physics, University of Minho, Braga, Portugal (AQ, DL-F, MF-R, JMG-M); and Universidad Politécnica de Cataluña, Terrasa, Spain (LQ).
authors: Jaume
authors: J
authors: Pauné
authors: Antonio
authors: A
authors: Queiros
authors: Daniela
authors: D
authors: Lopes-Ferreira
authors: Miguel
authors: M
authors: Faria-Ribeiro
authors: Lluisa
authors: L
authors: Quevedo
authors: Jose Manuel
authors: JM
authors: Gonzalez-Meijome
mesh_terms: D003261:Contact Lenses; D019781:Corneal Topography; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000628:therapy*; D011474:Prosthesis Design; D017755:Prosthesis Fitting; D012029:Refraction, Ocular / Q000502:physiology; D055815:Young Adult