title: Central and peripheral autorefraction repeatability in normal eyes.
abstract: OBJECTIVE
  To determine the between-visit repeatability of peripheral autorefraction measurements using the Grand Seiko WAM-5500 in normal eyes.
  
  
  METHODS
  Cycloplegic autorefraction of the right eye was measured on 25 myopic young adults using a modified Grand Seiko autorefractor. Measurements were made centrally (along the line of sight) and ±20, ±30, and ±40 degrees from the line of sight in the horizontal meridian at two visits separated by 1 to 15 days. Five autorefraction measurements at each location were converted to vector space and averaged. Relative peripheral refraction (RPR) was calculated as the difference between the peripheral and central spherical equivalent. Between-visit repeatability was evaluated by plotting the difference versus the mean of the measurements at the two visits (bias) and by calculating the 95% limits of agreement (LoA).
  
  
  RESULTS
  The mean (±SD) age and spherical-equivalent refractive error centrally (at visit 1) were 24.0 ± 1.3 years and -3.45 ± 1.42 diopters (D), respectively. There was no significant between-visit bias for any refractive component evaluated (M, J0, J45, and RPR) at any location measured (all p > 0.05). The 95% LoA of defocus (M) was ±0.21 D centrally and increased with increasing eccentricity to ±0.73 and ±0.88 D at 40 degrees nasally and temporally on the retina, respectively. The 95% LoA of RPR increased with increasing eccentricity to ±0.67 and ±0.82 D at 40 degrees nasally and temporally on the retina, respectively.
  
  
  CONCLUSIONS
  In normal eyes, the repeatability of cycloplegic autorefraction was best centrally and decreased as eccentricity increased; however, repeatability in the far periphery was still better than previously reported between-visit repeatability for foveal cycloplegic subjective refraction. With clear knowledge of the repeatability of on- and off-axis cycloplegic autorefraction with the Grand Seiko, peripheral measurements can be properly interpreted in longitudinal studies.
authors: *BS †OD, PhD, FAAO University of Houston, College of Optometry, Houston, Texas (both authors).
authors: Kelly E
authors: KE
authors: Moore
authors: David A
authors: DA
authors: Berntsen
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D009184:Mydriatics / Q000008:administration & dosage; D009216:Myopia / Q000503:physiopathology*; D011680:Pupil / Q000187:drug effects; D012029:Refraction, Ocular / Q000502:physiology*; D015203:Reproducibility of Results; D014331:Tropicamide / Q000008:administration & dosage; D014787:Vision Tests / Q000295:instrumentation; D055815:Young Adult
chemical_list: D009184:Mydriatics; D014331:Tropicamide