title: Effect of cycloplegia on the refractive status of children: the Shandong children eye study.
abstract: OBJECTIVE
  To determine the effect of 1% cyclopentolate on the refractive status of children aged 4 to 18 years.
  
  
  METHODS
  Using a random cluster sampling in a cross-sectional school-based study design, children with an age of 4-18 years were selected from kindergardens, primary schools, junior and senior high schools in a rural county and a city. Auto-refractometry was performed before and after inducing cycloplegia which was achieved by 1% cyclopentolate eye drops.
  
  
  RESULTS
  Out of 6364 eligible children, data of 5999 (94.3%) children were included in the statistical analysis. Mean age was 10.0±3.3 years (range: 4-18 years). Mean difference between cycloplegic and non-cycloplegic refractive error (DIFF) was 0.78±0.79D (median: 0.50D; range: -1.00D to +10.75D). In univariate analysis, DIFF decreased significantly with older age (P<0.001;correlation coefficient r:-0.24), more hyperopic non-cycloplegic refractive error (P<0.001;r = 0.13) and more hyperopic cycloplegic refractive error (P<0.001;r = 0.49). In multivariate analysis, higher DIFF was associated with higher cycloplegic refractive error (P<0.001; standardized regression coefficient beta:0.50; regression coefficient B: 0.19; 95% confidence interval (CI): 0.18, 0.20), followed by lower intraocular pressure (P<0.001; beta: -0.06; B: -0.02; 95%CI: -0.03, -0.01), rural region of habitation (P = 0.001; beta: -0.04; B: -0.07; 95%CI: -0.11, -0.03), and, to a minor degree, with age (P = 0.006; beta: 0.04; B: 0.009; 95%CI: 0.003, 0.016). 66.4% of all eyes with non-cycloplegic myopia (≤-0.50D) remained myopic after cycloplegia while the remaining 33.6% of eyes became emmetropic (18.0%) or hyperopic (15.7%) under cycloplegia. Prevalence of emmetropia decreased from 37.5% before cycloplegia to 19.8% after cycloplegia while the remaining eyes became hyperopic under cycloplegia.
  
  
  CONCLUSIONS
  The error committed by using non-cycloplegic versus cycloplegic refractometry in children with mid to dark-brown iris color decreased with older age, and in parallel manner, with more myopic cycloplegic refractive error. Non-cycloplegic refractometric measures lead to a misclassification of refractive error in a significant proportion of children.
authors: The First College of Clinical Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China; Department of Ophthalmology, The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan Shandong, China.
authors: Yuan Yuan
authors: YY
authors: Hu
authors: The First College of Clinical Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China.
authors: Jian Feng
authors: JF
authors: Wu
authors: Department of Ophthalmology, The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan Shandong, China.
authors: Tai Liang
authors: TL
authors: Lu
authors: Eye Institute of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China.
authors: Hui
authors: H
authors: Wu
authors: Department of Ophthalmology, The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan Shandong, China.
authors: Wei
authors: W
authors: Sun
authors: Department of Ophthalmology, The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan Shandong, China; Eye Institute of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China.
authors: Xing Rong
authors: XR
authors: Wang
authors: Department of Ophthalmology, The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan Shandong, China; Eye Institute of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China.
authors: Hong Sheng
authors: HS
authors: Bi
authors: Department of Ophthalmology, Medical Faculty Mannheim of the Ruprecht-Karls-University Heidelberg, Seegartenklinik Heidelberg, Germany.
authors: Jost B
authors: JB
authors: Jonas
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002681:China; D003430:Cross-Sectional Studies; D003519:Cyclopentolate / Q000494:pharmacology*; D005127:Eye Color; D005260:Female; D006801:Humans; D007498:Iris / Q000187:drug effects; D008297:Male; D009184:Mydriatics / Q000494:pharmacology*; D015995:Prevalence; D012029:Refraction, Ocular / Q000187:drug effects*; D012030:Refractive Errors / Q000175:diagnosis / Q000453:epidemiology*
chemical_list: D009184:Mydriatics; D003519:Cyclopentolate