Abstract
Purpose: :
To determine the prevalence of strabismus and heterophoria in children between 3.0 and 9.1 years of age who are members of a Native American population with a known high prevalence of astigmatism.
Methods: :
Subjects were 595 children enrolled in Head Start, kindergarten, or first grade during September 2005 through September 2007 in schools on the Tohono O’odham Reservation. Distance and near unilateral and alternate cover tests were performed on each child by an ophthalmologist or optometrist.
Results: :
Strabismus was detected in 1.0% of subjects. Two subjects (0.34%) were found to have esotropia and four subjects (0.67%) had exotropia. Heterophoria was detected in 3.7% of subjects, with exophoria accounting for the majority (91%) of these.
Conclusions: :
The prevalence of strabismus in this study is lower than previously published studies of children, where the prevalence has been reported to range from 1.3% in 6 to 12-year-old Japanese children (Matsuo et al, Ophthalmic Epidemiology, 2005) to 2.4% in Hispanic and 2.5% in African American children 6-72 months old (MEPEDS, Ophthalmology, 2007) to 3% in Minnesota children ≤6 years of age (Govindan et al, Ophthalmology, 2005 and Greenberg et al, Ophthalmology, 2007) to 5.3% in entry-level school children in Wales (Graham, British Journal of Ophthalmology, 1974). Few studies have focused specifically on the prevalence of heterophoria in this age group. However, one study reported esophoria at near in 7% and exophoria at near in 32% of kindergartners in a U.S. community (Walline et al, Optometry and Vision Science, 1998), values that are higher than heterophoria prevalence values in our population.
Keywords: strabismus • development • clinical (human) or epidemiologic studies: prevalence/incidence