ABSTRACT NUMBER - 1602

THE DEVELOPMENT AND PREVALENCE OF ASTIGMATISM AND ITS ASSOCIATION WITH REFRACTIVE ERROR AND VISUAL IMPAIRMENT IN PRESCHOOL CHILDREN – THE SYDNEY PAEDIATRIC EYE DISEASE STUDY


Sonia Afsari, Kathryn A Rose, Jody S Leone, Paul Mitchell

Meeting:  2012 RANZCO


SESSION INFORMATION

Date: 26 Nov 2012

Session Title: FREE PAPERS

Session Time: 4:00 pm - 5:30 pm

Purpose:
To determine the age and ethnicity-specific prevalence of astigmatism and its association with ametropia and visual impairment in Australian pre-school-aged children.

Method:
A total of 1370 children (6–72months) were included in the report having completed cycloplegic refraction. Astigmatism was defined as cylindrical refractive error ?1.50 dioptres (D) in the worse eye. The astigmatism type’s are with-the-rule (WTR) (+cylinder axis90 ± 15),against-the-rule (ATR) (+cylin-der axis 180 ± 15);all other orientations were con-sidered oblique (OBL).Visual impairment (VI) was defined as the best presenting VA < 6/15 in children aged < 48 months and < 6/12 in children aged ?48months. Results: Prevalence of astigmatism ?1.50 D was 9.9%.The prevalence of WTR, ATR and OBL astigma-tism ?1.50 D was 6.6%, 1.6%, 1.5% respectively. There was a lower prevalence of astigmatism in Euro-pean-Caucasian (6.9%) to East-Asian (13.1%), South Asian (13.8%) and Middle-Eastern (16.0%) children (p < 0.05). These ethnic differences were consistently found in WTR-astigmatism, however no ethnic differ-ences were noted in prevalence of ATR/OBL-astigma-tism. In age-adjusted logistic regression models, the prevalence of astigmatism increased with myopia ??0.50 D (OR:2.4 (CI:1.1–5.3)) and hyperopia > 3.0 D (OR:2.8 (CI:1.5–5.2)).Hyperopia of > 2.0 D was associ-ated with increased prevalence of WTR-astigmatism (OR:2.3 (CI:1.4–3.8)). Higher hyperopia of SE > 3.0 D was associated with increased prevalence of OBL-astigmatism (OR:7.2 (CI:2.1–24.7)). However an increased prevalence of ATR-astigmatism was only found with high myopia SE < ?1.0 D (OR:5.4 (CI:1.2–25.5)). An increasing prevalence of VI was found with increasing astigmatism (OR:25.2 (CI: 10.3–61.5)) with astigmatism > 2.5 D).

Conclusions:
Ethnic differences in astigmatism were found in this very young population of Australian children predominately European-Caucasian ethnicity yet with significant proportion of East-Asian, South-Asian and Middle-Eastern origin. Important associa-tions of increasing astigmatism and its sub-types were found with increasing ametropia and VI. This report provides population-based data on the natural devel-opment of astigmatism and further support the need for screening of astigmatism in this young age.

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