Purpose
To determine demographic and refractive risk factors for astigmatism among Head Start preschoolers in the Vision in Preschoolers (VIP) Study.
Methods
Head Start preschoolers (aged 3 to 5 years, over-represented with vision problems) were enrolled into the multi-center, cross-sectional VIP Study. All children underwent comprehensive eye examinations, including monocular visual acuity (VA), stereoacuity, and cycloplegic refraction. Astigmatism was defined by the presence of > 1.5 diopters (D) cylinder in either eye, measured with cycloplegic refraction. The odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) associated with age, gender, ethnicity and spherical equivalent were estimated using logistic regression models.
Results
Among 4040 VIP participants, 505 (12.5%) had astigmatism. Astigmatism was with-the-rule in 428 (84.8%), against-the-rule in 23 (4.6%) and oblique in 54 (10.7%). In multivariate analyses for all types of astigmatism (Table 1), African-American, Hispanic and Asian children were more likely to be astigmatic when compared with Caucasian children (all p<0.02). The OR for myopic children (≤ -1.0 D) relative to emmetropic children was 4.6 (95% CI: 2.9 - 6.8), whereas the OR for hyperopic children (≥ 2.0 D) was 1.3 (95% CI: 1.1 -1.6). The association between spherical equivalent refractive error and astigmatism was not linear (Figure 1). There was a trend of increasing risk of astigmatism with older children (linear trend p=0.12). The analysis for the risk factors of with-the-rule astigmatism provided similar results as all types of astigmatism.
Conclusions
Among Head Start preschoolers, Hispanic ethnicity, African-American and Asian race, and myopic and hyperopic refractive error were associated with increased risk of astigmatism, consistent with findings from the population-based Multi-ethnic Pediatric Eye Disease and Baltimore Pediatric Eye Disease studies.
Keywords: 428 astigmatism •
464 clinical (human) or epidemiologic studies: risk factor assessment