Factors Associated with Childhood Strabismus: Findings from a Population-Based Study
Received 19 August 2005; accepted 13 February 2006. published online 03 May 2006.
Purpose
To describe strabismus prevalence and associated factors in a representative sample of 6-year-old Australian children.
Design
Population-based cross-sectional study.
Participants
One thousand seven hundred thirty-nine predominantly 6-year-old children resident in Sydney examined in 2003 and 2004.
Methods
Cover testing was performed at near and distance fixation, and with spectacles if worn. Logarithm of the minimum angle of resolution visual acuity was measured in both eyes before and after pinhole correction, after correcting any cylindrical refraction >0.50 diopters and with spectacles, if worn. Cycloplegic autorefraction (cyclopentolate) and detailed dilated fundus examination were performed. Each child’s medical and perinatal histories were sought in a detailed parental questionnaire.
Main Outcome Measures
Strabismus was defined as any heterotropia at near or distance fixation, or both, on cover testing. Microstrabismus was defined as a deviation of fewer than 10 prism diopters.
Results
Strabismus was diagnosed in 48 children (2.8% of the population), 5 of whom had previously undergone surgical correction; 26 children (54%) had esotropia, 14 (29%) had exotropia, 7 (15%) had microstrabismus, and 1 child had VIth cranial nerve palsy. Prematurity was associated with a 5-fold increase in the risk of esotropia (odds ratio, 5.0; 95% confidence interval, 1.8–14.1). Visual impairment (with presenting correction) was significantly more common in children with (22.9%) than without (1.3%) strabismus (P<0.0001). The presence of strabismus was significantly associated with hyperopia, astigmatism, anisometropia, and amblyopia (P<0.0001).
Conclusions
This report documents the prevalence of strabismus and its relation to other ocular signs and visual impairment in a representative sample of Australian school children. Presence of strabismus was significantly associated with prematurity.
1Department of Ophthalmology, Centre for Vision Research, Westmead Hospital, and Westmead Millennium Institute, Sydney, Australia.
2School of Applied Vision Sciences, Faculty of Health Sciences, University of Sydney, Sydney, Australia.
Correspondence to Paul Mitchell, MD, PhD, Department of Ophthalmology, Center for Vision Research, University of Sydney, Westmead Hospital, Hawkesbury Road, Westmead, NSW, Australia, 2145.
Manuscript no. 2005-781.
The authors have no proprietary interests related to the article.
The Sydney Myopia Study is supported by the National Health & Medical Research Council, Canberra, Australia (grant no.: 253732); Westmead Millennium Institute, University of Sydney, Sydney, Australia; and Vision Co-operative Research Centre, University of New South Wales, Sydney, Australia.
ABSTRACT