title: Assessment of the accuracy of the crossed-cylinder aberroscope technique.
abstract: Simulations of the optics of the Howland crossed-cylinder aberroscope technique show that errors in alignment, data collection, and analysis can lead to unexpected asymmetries of the determined aberrations in a rotationally symmetric system. In particular, coma can be incorrectly indicated. The magnitude of the error in aberration measurement depends on the magnitude of the alignment, data collection, and alignment errors. These findings indicate that the tolerances for setting up the technique and data collection should be analyzed thoroughly before quantitative significance is given to the determined aberration coefficients.
authors.affiliation: Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: G
authors.initials: G
authors.lastname: Smith
authors.forename: R A
authors.initials: RA
authors.lastname: Applegate
authors.forename: D A
authors.initials: DA
authors.lastname: Atchison
mesh_terms: D003198:Computer Simulation; D005069:Evaluation Studies as Topic; D008962:Models, Theoretical; D055095:Optics and Photonics / Q000295:instrumentation*; D012030:Refractive Errors / Q000175:diagnosis*