title: Plusoptix Vision Screener: the accuracy and repeatability of refractive measurements using a new autorefractor.
abstract: BACKGROUND
  The Plusoptix Vision Screener (PVS) is a new non-cycloplegic videoretinoscopy autorefractor. Refractive accuracy may affect its performance as a screening tool.
  
  
  OBJECTIVE
  Study 1: To determine the intra- and interobserver variability of PVS measurements. Study 2: To compare PVS measurements with gold-standard manual cycloplegic retinoscopy (MCR).
  
  
  METHODS
  Study 1: PVS refraction of 103 children with mean (SD) age 5.5 (0.6) years by two observers. Study 2: PVS and MCR refraction of 126 children with mean (SD) age 5.5 (1.5) years, including 43 children with manifest strabismus >/=5 PD, comparing mean spherical equivalent (MSE) and Jackson cross cylinders J(0) and J(45).
  
  
  RESULTS
  Study 1: Repeatability coefficients (observer 1): MSE: 0.63 D, J(0): 0.24 D, J(45): 0.18 D; those of observer 2 were nearly identical. The mean difference (95% limits of agreement) between the two observers for MSE, J(0) and J(45) were, respectively, 0.03 (-0.62 to 0.68 D), -0.008 (-0.25 to 0.23 D) and 0.013 (-0.18 to 0.20) D. Study 2: MSE tended to be lower on PVS than MCR, with differences of up to 8.00 D. Less than 20% of values were within +/-0.50 D of each other. Agreement was better for J(0) and J(45). Strabismus was associated with an odds ratio of 3.7 (95% CI 1.3 to 10.5) of the PVS failing to obtain a reading.
  
  
  CONCLUSIONS
  The PVS may underestimate children's refractive error.
authors.affiliation: Eye Treatment Centre, West Suffolk Hospital NHS Trust, Hardwick Lane, Bury St Edmunds IP33 2QZ, UK.
authors.forename: A H
authors.initials: AH
authors.lastname: Dahlmann-Noor
authors.forename: O
authors.initials: O
authors.lastname: Comyn
authors.forename: V
authors.initials: V
authors.lastname: Kostakis
authors.forename: A
authors.initials: A
authors.lastname: Misra
authors.forename: N
authors.initials: N
authors.lastname: Gupta
authors.forename: J
authors.initials: J
authors.lastname: Heath
authors.forename: J
authors.initials: J
authors.lastname: Brown
authors.forename: A
authors.initials: A
authors.lastname: Iron
authors.forename: S
authors.initials: S
authors.lastname: McGill
authors.forename: K
authors.initials: K
authors.lastname: Vrotsou
authors.forename: A J
authors.initials: AJ
authors.lastname: Vivian
mesh_terms: D000550:Amblyopia / Q000175:diagnosis; D002648:Child; D002675:Child, Preschool; D003936:Diagnosis, Computer-Assisted; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000175:diagnosis*; D042261:Retinoscopes; D042262:Retinoscopy / Q000379:methods; D012680:Sensitivity and Specificity; D014741:Video Recording