title: Screening for refractive errors with the Topcon PR2000 Pediatric Refractometer.
abstract: OBJECTIVE
  The PR2000 (Topcon, Tokyo, Japan) is a photorefractor that has been used in a population study comparing different methods of screening preschool children. The present study was conducted to determine the accuracy of the device in a largely clinical population.
  
  
  METHODS
  Two hundred twenty-two children less than 8 years of age were included. All children were examined by an orthoptist using the PR2000 without inducing cycloplegia. All children then underwent retinoscopy with cycloplegia by an examiner who was unaware of the results from the PR2000 examination.
  
  
  RESULTS
  The PR2000 gave a numerical reading for 90% of the children's right eyes and the message "Out of range" for a further 5%. The readings underestimated the amount of hypermetropic or astigmatic refractive error found on retinoscopy by an amount proportional to the magnitude of the refractive error. Agreement with retinoscopy for the axis of astigmatism more than 0.75 D was moderately good (intraclass correlation coefficient [ICC] = 0.63). The PR2000 was more useful as a screener, especially for anisometropia for which it was 91% sensitive and 92% specific. The repeatability was good for sphere (ICC = 0.74), less so for astigmatism (ICC = 0.59), and better than the optometrist for anisometropia (ICC = 0.38). The presence of nonrefractive diagnoses and the age of the children examined made little difference in the screening results.
  
  
  CONCLUSIONS
  The PR2000 underestimated hypermetropic refractive errors when used without cycloplegia. However, it was at least as good a screening device as other similar instruments, especially when judged by its ability to detect anisometropia and the repeatability of the results.
authors.affiliation: Dept. of Ophthalmology, Bristol Eye Hospital, United Kingdom. cathy.williams@bristol.ac.uk
authors.forename: C
authors.initials: C
authors.lastname: Williams
authors.forename: R
authors.initials: R
authors.lastname: Lumb
authors.forename: I
authors.initials: I
authors.lastname: Harvey
authors.forename: J M
authors.initials: JM
authors.lastname: Sparrow
mesh_terms: D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D012030:Refractive Errors / Q000175:diagnosis*; D015203:Reproducibility of Results; D015351:Vision Screening / Q000592:standards*; D014787:Vision Tests / Q000295:instrumentation*