Abstract
Purpose: :
To determine the presence of refractive amblyogenic risk factors in the varying ages of a low income, underserved, preschool population.
Methods: :
In a multi-center (n > 100) study eye examinations of 6476 children ages 6 months- 6 years were performed. Children were recruited from Early Intervention Programs and most were from non-Caucasian, low-income families.Hyperopia and myopia were defined as 1 D or more in each principal meridian. Astigmatism was defined as at least 1 D difference in refractive error between the two principal meridians. Amblyogenic risk factors were defined as bilateral spherical refractive error ≥ + 4 D or - 6 D; astigmatic refractive error ≥ 2.50 diopters; anisometropic refractive error ≥ 1.50 D in regard to hyperopia and astigmatism; and ≥ 2 D of myopic anisometropia.
Results: :
7 percent of the group were identified as having isometropic amblyogenic risk factors. The birth to 1 year olds revealed these risk factors in 11% of the hyperopes and none of the myopes. The 1-2 year olds in 3.5 % of hyperopes and 0.6% of myopes, the 2-3 year olds in 3.27% of hyperopes and 0.4% of myopes, the 3-4year olds in 4.35%of hyperopes and 0.27% of myopes, the 4-5 year olds in 4.52% of hyperopes and 0.34% of myopes, the 5-6 year olds in 4.15% of hyperopes and 0.36% of myopes, and the 6+ group in 6% of hyperopes and 1% of myopes.Isometropic amblyogenic risk factors due to high astigmatic corrections were identified in 6.74 % of the birth to one year olds. The 1-2 year olds showed these risks in 4.24 %, the 2-3 year olds in 5.72 %, the 3-4 year olds in 6.22 %, the 4-5 year olds in 5.828 %, the 5-6 year olds in 4.96% and 6+ age group in 3% of those evaluated.The prevalence of anisometropic amblyogenic risk factors was less than that of isometropic amblyogenic risk factors. 2 percent of the entire group were at risk for anisometropic amblyopia. 0.8 % of the group showed a hyperopic difference of ≥ 1.5D, 0.04% showing a myopic difference of ≥ -2D. Anisometropic astigmatism was more prevalent with 1.45 % showing ≥ 1.50 D difference in cylindrical power. No statistically significant differences were present when broken down by age
Conclusions: :
Isometropic amblyopia accounts for 1-2 % of all refractive amblyopia in the general population. 7% of the children in the study were positive for the risk. Uncorrected hyperopic and astigmatic corrections pose the greatest risk for amblyopia development. In our low income, preschool population the 3-5 year old age group demonstrates the greatest need for identification and treatment of isometropic refractive amblyopia. The results of this study confirm the importance of early detection and intervention of childhood vision problems, such as amblyopia, in order to maximize a child’s development and learning potential.
Keywords: amblyopia • refractive error development • visual development