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Development of phoria in children
J J Walline1, D O Mutti, K Zadnik
1The Ohio State University College of Optometry, Columbus 43210-1240, USA.
Summary
Phoria prevalence in children is typically orthophoric at distance. Near phoria shows a shift towards esophoria with age, with exophoria decreasing and esophoria increasing from kindergarten to fifth grade.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Vision Science
Background:
- Phoria prevalence data in children is limited compared to adults.
- This study addresses the scarcity of information on childhood phoria.
- Utilizes data from the Orinda Longitudinal Study of Myopia.
Purpose of the Study:
- To document the prevalence of phoria in a large, population-based sample of nonstrabismic children.
- To investigate the changes in phoria with age in childhood.
- To provide normative data for childhood phoria.
Main Methods:
- Employs modified clinical technique vision screening.
- Collects both cross-sectional (N=1495) and longitudinal (N=469) data.
- Uses cover tests to classify phoria (orthophoria, esophoria, exophoria) in 2-delta steps.
Main Results:
- 97% of children are orthophoric at distance, with no significant age-related changes.
- Near phoria exhibits a more normal distribution.
- Between kindergarten and fifth grade, exophoria decreased by 10.8% and esophoria increased by 5.5%.
Conclusions:
- Children are generally orthophoric or exophoric at near distances.
- A convergent shift in near phoria occurs as children age.
- Findings highlight age-related changes in binocular vision in children.