title: Pre- and Postcycloplegic Refractions in Children and Adolescents.
abstract: OBJECTIVE
  To determine the difference between cycloplegic and non-cycloplegic refractive error and its associated factors in Chinese children and adolescents with a high prevalence of myopia.
  
  
  METHODS
  A school-based study including 1565 students aged 6 to 21 years was conducted in 2013 in Ejina, Inner Mongolia, China. Comprehensive eye examinations were performed. Pre-and postcycloplegic refractive error were measured using an auto-refractor. For cycloplegic refraction, one drop of topical 1.0% cyclopentolate was administered to each eye twice with a 5-minute interval and a third drop was administered 15 minutes after the second drop if the pupil size was less than 6 mm or if the pupillary light reflex was still present.
  
  
  RESULTS
  Two drops of cyclopentolate were found to be sufficient in 59% of the study participants while the other 41% need an additional drop. The prevalence of myopia was 89.5% in participants aged over 12 years and 68.6% in those aged 12 years or younger (P<0.001). When myopia was defined as spherical equivalent (SE) of less than -0.5 diopter (D), the prevalence estimates were 76.7% (95% confidence interval [CI] 74.6-78.8) and 54.1% (95%CI 51.6-56.6) before and after cycloplegic refraction, respectively. When hyperopia was defined as SE of more than 0.5D, the prevalence was only 2.8% (95%CI 1.9-3.6) before cycloplegic refraction while it was 15.5% (95%CI 13.7-17.3) after cycloplegic refraction. Increased difference between cycloplegic and non-cycloplegic refractive error was associated with decreased intraocular pressures (P = 0.01).
  
  
  CONCLUSIONS
  Lack of cycloplegia in refractive error measurement was associated with significant misclassifications in both myopia and hyperopia among Chinese children and adolescents. Decreased intraocular pressure was related to a greater difference between cycloplegic and non-cycloplegic refractive error.
authors.affiliation: Department of Ophthalmology, the Affiliated Hospital of Inner Mongolia Medical University, Inner Mongolia, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhu
authors.affiliation: Department of Ophthalmology, the Affiliated Hospital of Inner Mongolia Medical University, Inner Mongolia, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Ophthalmology, the Affiliated Hospital of Inner Mongolia Medical University, Inner Mongolia, China.
authors.forename: Xianrong
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Ophthalmology, the Affiliated Hospital of Inner Mongolia Medical University, Inner Mongolia, China.
authors.forename: Dayong
authors.initials: D
authors.lastname: Yang
authors.affiliation: Department of Ophthalmology, the Affiliated Hospital of Inner Mongolia Medical University, Inner Mongolia, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Guo
authors.affiliation: Department of Ophthalmology, the Affiliated Hospital of Inner Mongolia Medical University, Inner Mongolia, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Ophthalmology, the Affiliated Hospital of Inner Mongolia Medical University, Inner Mongolia, China.
authors.forename: Xinxia
authors.initials: X
authors.lastname: Jing
authors.affiliation: Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Medical College of Soochow University, Suzhou, China.
authors.forename: Chen-Wei
authors.initials: CW
authors.lastname: Pan
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002681:China; D003519:Cyclopentolate / Q000008:administration & dosage; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000175:diagnosis* / Q000473:pathology; D009216:Myopia / Q000175:diagnosis* / Q000453:epidemiology; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000175:diagnosis / Q000503:physiopathology; D042262:Retinoscopy; D014787:Vision Tests; D055815:Young Adult
chemical_list: D003519:Cyclopentolate