title: Amplitude of accommodation in an 11- to 17-year-old Iranian population.
abstract: OBJECTIVE
  The aim was to determine normal values of accommodative amplitude (AA) during adolescence in Iran.
  
  
  METHODS
  In this cross-sectional study, sampling was done from high school students in Kermanshah in 2015 through a multi-stage cluster sampling method and selected students were invited to participate in the study. Examinations were performed on-site at each sampled high school. All students had visual acuity and refractive examination followed by measurement of AA. Accommodative amplitude was tested with Donder's push-up method using a Royal Air Force (RAF) near point rule.
  
  
  RESULTS
  Of the 1,070 selected students, 901 were included in the study and their mean age was 14.4 ± 1.7 years. Mean AA in this study was 11.53 ± 3.02 D (range: 5.00-28.50 D). Mean AA was 15.33 D in 11-year-olds and significantly decreased with age, until it reached 10.40 D in the 17-year-old age group. Mean AA in boys and girls were 10.09 ± 2.48 D and 11.65 ± 3.03 D, respectively. Based on the multiple linear regression model, younger age (coefficient = -0.774) and female gender (coefficient = 1.060) significantly associated with AA.
  
  
  CONCLUSIONS
  This study showed that the AA in Iranian teenagers is lower than that calculated with Hofstetter's formula. It is important to take account of this point when making diagnostic and therapeutic decisions.
authors.affiliation: Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.|Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Hashemi
authors.affiliation: Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
authors.forename: Payam
authors.initials: P
authors.lastname: Nabovati
authors.affiliation: Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Abbas Ali
authors.initials: AA
authors.lastname: Yekta
authors.affiliation: Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Hadi
authors.initials: H
authors.lastname: Ostadimoghaddam
authors.affiliation: Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Samira
authors.initials: S
authors.lastname: Forouzesh
authors.affiliation: Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Negareh
authors.initials: N
authors.lastname: Yazdani
authors.affiliation: Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Khabazkhoob
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology; D000293:Adolescent; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D012030:Refractive Errors / Q000503:physiopathology; D012727:Sex Characteristics
keywords: Middle East; amplitude of accommodation; binocular vision; normal children