title: Cycloplegic refraction is the gold standard for epidemiological studies.
abstract: Many studies on children have shown that lack of cycloplegia is associated with slight overestimation of myopia and marked errors in estimates of the prevalence of emmetropia and hyperopia. Non-cycloplegic refraction is particularly problematic for studies of associations with risk factors. The consensus around the importance of cycloplegia in children left undefined at what age, if any, cycloplegia became unnecessary. It was often implicitly assumed that cycloplegia is not necessary beyond childhood or early adulthood, and thus, the protocol for the classical studies of refraction in older adults did not include cycloplegia. Now that population studies of refractive error are beginning to fill the gap between schoolchildren and older adults, whether cycloplegia is required for measuring refractive error in this age range, needs to be defined. Data from the Tehran Eye Study show that, without cycloplegia, there are errors in the estimation of myopia, emmetropia and hyperopia in the age range 20-50, just as in children. Similar results have been reported in an analysis of data from the Beaver Dam Offspring Eye Study. If the only important outcome measure of a particular study is the prevalence of myopia, then cycloplegia may not be crucial in some cases. But, without cycloplegia, measurements of other refractive categories as well as spherical equivalent are unreliable. In summary, the current evidence suggests that cycloplegic refraction should be considered as the gold standard for epidemiological studies of refraction, not only in children, but in adults up to the age of 50.
authors.affiliation: Research School of Biological Science, Australian National University, Canberra, ACT, Australia.|Division of Preventive Ophthalmology and State Key Laboratory in Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Ian G
authors.initials: IG
authors.lastname: Morgan
authors.affiliation: Department of Ophthalmology, San Luis Medical Center, Buenos Aires, Argentina.
authors.forename: Rafael
authors.initials: R
authors.lastname: Iribarren
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Akbar
authors.initials: A
authors.lastname: Fotouhi
authors.affiliation: Department of Ophthalmology, Poznan City Hospital, Poznan, Poland.|Chair of Ophthalmology, University of Warmia and Mazury, Olsztyn, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Grzybowski
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003951:Diagnostic Errors; D016021:Epidemiologic Studies; D006801:Humans; D007223:Infant; D008875:Middle Aged; D009184:Mydriatics / Q000008:administration & dosage*; D011680:Pupil / Q000187:drug effects*; D012015:Reference Standards; D012029:Refraction, Ocular / Q000187:drug effects*; D012030:Refractive Errors / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D009184:Mydriatics
keywords: cycloplegic refraction; epidemiological studies; refraction measurement