Prevalence of astigmatism in 6- to 72-month-old African American and Hispanic children: the Multi-ethnic Pediatric Eye Disease Study

Abstract

Purpose: To determine the age-, gender-, and ethnicity-specific prevalence of astigmatism in African American and Hispanic children aged 6 to 72 months.

Design: Population-based, cross-sectional study.

Participants: The Multi-Ethnic Pediatric Eye Disease Study is a population-based evaluation of the prevalence of vision disorders in children ages 6 to 72 months in Los Angeles County, California. Seventy-seven percent of eligible children completed a comprehensive eye examination. This report provides the results from 2994 African American and 3030 Hispanic children.

Methods: Eligible children in 44 census tracts were identified during an in-home interview and scheduled for a comprehensive eye examination and in-clinic interview. Cycloplegic autorefraction was used to determine refractive error.

Main outcome measures: The proportion of children with astigmatism defined as cylindrical refractive error ≥ 1.50 diopters (D) in the worse eye. The astigmatism type was defined as with-the-rule (WTR) (+ cylinder axis 90 ± 15 degrees) and against-the-rule (ATR) (+ cylinder axis 180 ± 15 degrees); all other orientations were considered oblique (OBL). The prevalence of astigmatism and its types were also determined for worse eye cylindrical refractive error ≥ 3.00 D.

Results: Prevalence of astigmatism ≥ 1.50 D was higher in Hispanic children compared with African American children (16.8% vs. 12.7%, respectively; P<0.0001). Hispanic children also showed a higher prevalence of astigmatism ≥ 3.00 D than African American children (2.9% vs. 1.0% respectively; P<0.0001). The prevalence of astigmatism ≥ 1.50 D showed a significant decreasing trend with age (P<0.0001). The prevalence of WTR, ATR, and OBL astigmatism ≥ 1.50 D was 13.9%, 0.6%, and 2.2%, respectively, in Hispanic children, and 7.8%, 2.2%, and 2.7%, respectively, in African American children.

Conclusions: We observed ethnicity-related differences in astigmatism prevalence in preschool children. The age-related decrease in astigmatism prevalence in preschool children likely reflects emmetropization.

Figure 1

Locally weighted regression lines derived for mean right eye cylindrical power, J0 and J45 as a function of age in months in African American and Hispanic children in the Multi-Ethnic Pediatric Eye Disease Study. Panel 1A: mean right eye cylindrical power. Panel 1B: mean right eye J0 (Cartesian) vector component of astigmatism. J0 is defined as (−C/2)*Cos2α, where α and C are axis and magnitude of cylindrical refractive error. Panel 1C: mean right eye J45 (oblique) vector component of astigmatism. J45 is defined as (−C/2)*Sin2α, where α and C are axis and magnitude of cylindrical refractive error. Gray shading represents 95% confidence interval of the estimated mean values.

Figure 1

Locally weighted regression lines derived for mean right eye cylindrical power, J0 and J45 as a function of age in months in African American and Hispanic children in the Multi-Ethnic Pediatric Eye Disease Study. Panel 1A: mean right eye cylindrical power. Panel 1B: mean right eye J0 (Cartesian) vector component of astigmatism. J0 is defined as (−C/2)*Cos2α, where α and C are axis and magnitude of cylindrical refractive error. Panel 1C: mean right eye J45 (oblique) vector component of astigmatism. J45 is defined as (−C/2)*Sin2α, where α and C are axis and magnitude of cylindrical refractive error. Gray shading represents 95% confidence interval of the estimated mean values.

Figure 2

Scatter plots of the power vector components of astigmatism in the youngest and oldest age groups of African American and Hispanic children in the Multi-Ethnic Pediatric Eye Disease Study. Each data point on a scatter plot represents the power vector expression of astigmatism for one eye using the 2-dimensional vector (J0, J45). The origin of the graph (0, 0) represents an eye free of astigmatism. Panel 2A: Right and left eyes of 6–11 month-old and 60–72 month-old African American children. Panel 2B: Right and left eyes of 6–11 month-old and 60–72 month-old Hispanic children. X axis: J0 vector components of right eye and left eye astigmatism. J0 is defined as (−C/2)*Cos2α, where α and C are axis and magnitude of cylindrical refractive error. Y axes: J45 vector components of right and left eye astigmatism. J45 is defined as (−C/2)*Sin2α, where α and C are axis and magnitude of cylindrical refractive error.

Figure 2

Scatter plots of the power vector components of astigmatism in the youngest and oldest age groups of African American and Hispanic children in the Multi-Ethnic Pediatric Eye Disease Study. Each data point on a scatter plot represents the power vector expression of astigmatism for one eye using the 2-dimensional vector (J0, J45). The origin of the graph (0, 0) represents an eye free of astigmatism. Panel 2A: Right and left eyes of 6–11 month-old and 60–72 month-old African American children. Panel 2B: Right and left eyes of 6–11 month-old and 60–72 month-old Hispanic children. X axis: J0 vector components of right eye and left eye astigmatism. J0 is defined as (−C/2)*Cos2α, where α and C are axis and magnitude of cylindrical refractive error. Y axes: J45 vector components of right and left eye astigmatism. J45 is defined as (−C/2)*Sin2α, where α and C are axis and magnitude of cylindrical refractive error.

Figure 3

Locally weighted regression lines derived for prevalence of astigmatism as a function of age in months for African American and Hispanic children in the Multi-Ethnic Pediatric Eye Disease Study. Panel 3A: Vertical axis shows the estimated prevalence of astigmatism ≥1.50 D in the worse eye (CYL ≥1.50 D). Panel 3B: Vertical axis shows the estimated prevalence of astigmatism ≥3.00 D in the worse eye (CYL ≥3.00 D). Gray shading represent 95% confidence interval of the estimated prevalence. CYL: cylindrical refractive error; D: diopters

Figure 4

Distribution of cylindrical power of the eye with greater absolute amount of cylinder, binned by 0.50 diopter (D) increments of cylinder power, stratified by age and ethnic group in the Multi-Ethnic Pediatric Eye Disease Study. Vertical axis shows the prevalence (%) of a given level of cylindrical refractive error. Horizontal axis shows cylindrical refractive error in 0.50 D intervals.

Figure 5

Bar graph of proportions of subtypes of astigmatism relative to overall cases of worse-eye astigmatism ≥1.50 diopters (D), by age group, in African American (5A) and Hispanic (5B) children in the Multi-Ethnic Pediatric Eye Disease Study. WTR: With-the-rule astigmatism, defined as astigmatism with the axis of greatest power within +/− 15 degrees of 90, i.e., in the range [75–105°]; ATR: Against-the-rule astigmatism, defined as astigmatism with the axis of greatest power within +/− 15 degrees of 180, i.e., in the range [1–15°] or [165–180°]; OBL: Oblique axis astigmatism, which includes all other orientations (axis of greatest power in the range [106–164°] or [16–74°]); AA=African American; H=Hispanic. X axis shows age groups in months. Y axis shows percentage of overall number of cases of worse-eye astigmatism ≥1.50 D. The worse eye is defined as the eye with the largest absolute amount of cylindrical refractive error. In ties for magnitude, oblique astigmatism is considered worse than WTR or ATR astigmatism. There were no ties for magnitude between ATR and WTR astigmatism ≥1.50 D.