title: Astigmatism in underserved rural areas: a population based study.
abstract: Studying the prevalence of astigmatism and its related factors in underprivileged rural areas in Iran.
  
  
  
  Using random cluster sampling, two rural areas in the north and southwest of Iran were randomly selected, and 3851 persons over 1 year of age were invited to the study. In addition to recording demographics, retinoscopic refraction was conducted using baseline auto-refraction results. The prevalence of astigmatism was determined based on cylinder error cut-off points of 0.50 dioptre (D), 1.00, 2.00 and 3.00 D. Multiple logistic regression was used to assess variables' relationship with astigmatism.
  
  
  
  The prevalence of astigmatism as a cylinder error greater than 0.50 D was 35.6% (95% CI: 33.7-37.6); this was 34.0% (95% CI: 31.4-36.6) in women and 36.9% (95% CI: 33.9-39.9) in men. The lowest prevalence was seen in the 6-20 year old age group (13.6%) and the highest prevalence was found in individuals older than 70 years (82.5%). In the multiple logistic regression model, age and education level were significantly related to astigmatism. The prevalence rates of with-the-rule (WTR), against-the-rule (ATR), and oblique astigmatism were respectively 15.0%, 17.2%, and 3.5%. The prevalence of WTR astigmatism decreased with age, while the prevalence of ATR (and oblique astigmatism to a lesser extent) increased.
  
  
  
  The prevalence of astigmatism was similar to previous studies; however, there were considerable age-related changes. In particular, the prevalence of astigmatism in elderly people was substantial and of concern, particularly given that virtually none of this age group were wearing distance spectacles.
authors: Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.
authors: Hassan
authors: H
authors: Hashemi
authors: Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.
authors: Payam
authors: P
authors: Nabovati
authors: Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.
authors: Azam
authors: A
authors: Malekifar
authors: Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Abbasali
authors: A
authors: Yekta
authors: Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Hadi
authors: H
authors: Ostadimoghaddam
authors: Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.
authors: Ebrahim
authors: E
authors: Jafarzadehpur
authors: Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Khabazkhoob@yahoo.com.
authors: Mehdi
authors: M
authors: Khabazkhoob
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000453:epidemiology* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D008507:Medically Underserved Area; D008875:Middle Aged; D011159:Population Surveillance; D015995:Prevalence; D012029:Refraction, Ocular / Q000502:physiology*; D012424:Rural Population; D017678:Sex Distribution; D055815:Young Adult
keywords: against-the-rule; astigmatism; oblique; rural areas; with-the-rule