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Br J Ophthalmol 2006;90:597-601 doi:10.1136/bjo.2005.083154
  • Clinical science
    • Extended reports

Prevalence and associations of anisometropia and aniso-astigmatism in a population based sample of 6 year old children

  1. S C Huynh1,
  2. X Y Wang3,
  3. J Ip1,
  4. D Robaei1,
  5. A Kifley1,
  6. K A Rose2 and
  7. P Mitchell1
  1. 1Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, Sydney, Australia
  2. 2School of Applied Vision Sciences, Faculty of Health Sciences, University of Sydney, Sydney, Australia
  3. 3Vision Cooperative Research Centre, School of Optometry, University of New South Wales, Sydney, Australia
  1. Correspondence to: Paul Mitchell MD, PhD, FRCOphth, Centre for Vision Research, Department of Ophthalmology, University of Sydney, Hawkesbury Road, Westmead, NSW 2145, Australia; paul_mitchell{at}wmi.usyd.edu.au
  • Accepted 4 January 2006

Abstract

Aim: To study the distribution of anisometropia and aniso-astigmatism in young Australian children, together with clinical and ocular biometry relations.

Method: The Sydney Myopia Study examined 1765 predominantly 6 year old children from 34 randomly selected Sydney schools during 2003–4. Keratometry, cycloplegic autorefraction, and questionnaire data were collected.

Results: Spherical equivalent (SE) anisometropia (≥1 dioptre) prevalence was 1.6% (95% confidence interval (CI) 1.1% to 2.4%). Aniso-astigmatism (≥1D) prevalence was 1.0% (CI: 0.6% to 1.6%). Both conditions were significantly more prevalent among moderately hyperopic (SE ≥2.0D) than mildly hyperopic (SE 0.5–1.9D) children. Myopic children (SE ≤−0.5D) had higher anisometropia prevalence. Neither condition varied by age, sex, or ethnicity. In multivariate analyses, anisometropia was significantly associated with amblyopia, odds ratio (OR) 29, (CI: 8.7 to 99), exotropia (OR 7.7, CI: 1.2 to 50), and neonatal intensive care unit (NICU) admission (OR 3.6, CI: 1.1 to 12.6). Aniso-astigmatism was significantly associated with amblyopia (OR 8.2, CI: 1.4 to 47), maternal age >35 years (OR 4.0, CI: 1.3 to 11.9), and NICU admission (OR 4.6, CI: 1.2 to 17.2). Anisometropia resulted from relatively large interocular differences in axial length (p<0.0001) and anterior chamber depth (p = 0.0009). Aniso-astigmatism resulted from differences in corneal astigmatism (p<0.0001).

Conclusion: In this predominantly 6 year old population, anisometropia and aniso-astigmatism were uncommon, had important birth and biometry associations, and were strongly related to amblyopia and strabismus.

Notes

  • Competing interests: The authors have no financial interest in any materials used in this study.

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