title: Comparing the relative peripheral refraction effect of single vision and multifocal contact lenses measured using an autorefractor and an aberrometer: A pilot study.
abstract: OBJECTIVE
  To compare the contributions of single vision (SVCL) and multifocal contact lenses (MFCL) to the relative peripheral refraction (RPR) profiles obtained via an autorefractor and an aberrometer in a pilot study.
  
  
  METHODS
  Two instruments, Shin-Nippon NVision K5001 (SN) and COAS-HD, were modified to permit open field PR measurements. Two myopic adults (CF, RB) were refracted (cycloplegia) under eight conditions: baseline (no CL); three SVCLs: Focus Dailies(®) (Alcon, USA), PureVision(®) (Bausch & Lomb, USA) and AirOptix(®) (Alcon, USA); and four MFCLs: AirOptix(®) (Alcon, USA), Proclear(®) Distant and Near (Cooper Vision, USA), and PureVision(®) (Bausch & Lomb, USA). CLs had a distance prescription of -2.00D and for MFCLs, a +2.50D Add was selected. Five independent measurements were performed at field angles from -40° to +40° in 10° increments with both instruments. The COAS-HD measures were analyzed at 3mm pupil diameter. Results are reported as a change in the relative PR profile, as refractive power vector components: M, J180, and J45.
  
  
  RESULTS
  Overall, at baseline, M, J180 and J45 measures obtained with SN and COAS-HD were considerably different only for field angles ≥±30°, which agreed well with previous studies. With respect to M, this observation held true for most SVCLs with a few exceptions. The J180 measures obtained with COAS-HD were considerably greater in magnitude than those acquired with SN. For SVCLs, the greatest difference was found at -40° for AirOptix SV (ΔCF=3.20D, ΔRB=1.56D) and for MFCLs it was for Proclear Distance at -40° (ΔCF=2.58D, ΔRB=1.39D). The J45 measures obtained with SN were noticeably different to the respective measures with COAS-HD, both in magnitude and sign. The greatest difference was found with AirOptix Multifocal in subject RB at -40°, where the COAS-HD measurement was 1.50D more positive. In some cases, the difference in the RPR profiles observed between subjects appeared to be associated with CL decentration.
  
  
  CONCLUSIONS
  For most test conditions, distinct differences were observed between the RPR measures obtained with the two modified instruments. The differences varied with CL design and centration. Although the pilot study supports the interchangeable use of the two instruments for on- and off-axis refraction in unaided eyes or eyes corrected with low/no spherical aberration; we advocate the use of the COAS-HD over the SN for special purposes like refracting through multifocal CLs.
authors: Brien Holden Vision Institute, Sydney, Australia; School of Optometry and Vision Sciences, UNSW, Sydney, Australia. Electronic address: r.bakaraju@brienholdenvision.org.
authors: Ravi C
authors: RC
authors: Bakaraju
authors: Brien Holden Vision Institute, Sydney, Australia; School of Optometry and Vision Sciences, UNSW, Sydney, Australia.
authors: Cathleen
authors: C
authors: Fedtke
authors: Brien Holden Vision Institute, Sydney, Australia; School of Optometry and Vision Sciences, UNSW, Sydney, Australia.
authors: Klaus
authors: K
authors: Ehrmann
authors: Brien Holden Vision Institute, Sydney, Australia; School of Optometry and Vision Sciences, UNSW, Sydney, Australia.
authors: Arthur
authors: A
authors: Ho
mesh_terms: D057128:Aberrometry / Q000295:instrumentation*; D000328:Adult; D003263:Contact Lenses, Hydrophilic; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000534:rehabilitation*; D010865:Pilot Projects; D012029:Refraction, Ocular / Q000502:physiology; D012031:Refractometry / Q000295:instrumentation*; D014787:Vision Tests; D014794:Visual Fields / Q000502:physiology*; D055815:Young Adult
keywords: Aberrómetro de frente de onda; Autorefractor; Autorrefractor; Lentes de contacto multifocales; Miopía; Multifocal contact lens; Myopia; Peripheral refraction; Refracción periférica; Wavefront aberrometer