title: A test eye for wavefront eye refractors.
abstract: OBJECTIVE
  A multi-site study was conducted to test feasibility of a modified automatic refractor style test eye as a test device for wavefront refractors of various types and to determine whether a) they could be measured and b) when measurements could be made, to see if they were similar. This study did not attempt to assess which instrument most accurately measures the aberrations of the test eye or human eye.
  
  
  METHODS
  Three automatic refractor style test eyes were modified for use as test devices for wavefront refractors. One had a simple spherical front surface, and two had additional aberrations added. The test eyes and holder were circulated to 11 test sites where attempts were made to measure them with eight different wave-front refractor systems.
  
  
  RESULTS
  Eight (100%) of the eight wavefront refractor systems tested successfully measured the test eyes. The systems did not give similar results for the same test eye. In some cases, coma was reported where none was present. Differences in reported defocus values reflect different approaches for compensating for the dispersion of the eye. A corneal topography system could measure and recognize the aberrations of the test eyes as well as the wavefront refractor systems tested. Interferometry, on the other hand, did not prove to be a successful method to assess the surface of the test eyes.
  
  
  CONCLUSIONS
  The test eye design may be used as a test device for wavefront refractor systems. This type of test eye can detect systematic differences between various wavefront refractors and can serve as a useful calibration and comparison tool.
authors.affiliation: ceccec@pacbell.net
authors.forename: Charles E
authors.initials: CE
authors.lastname: Campbell
mesh_terms: D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D004867:Equipment Design; D005123:Eye; D005240:Feasibility Studies; D006801:Humans; D066298:In Vitro Techniques; D008953:Models, Anatomic; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000175:diagnosis*