The Prevalence of Strabismus and Heterophoria in 3-6 Years Old Children in Bojnurd, Iran, in 2016-2017

Strabismus is one of the serious visual problems in children. Early diagnosis and treatment of strabismus at an early ages results in good treatment outcomes. In this regard, the aim of this study was to determine the prevalence of strabismus and heterophoria in children aged 3 to 6 years in city of Bojnurd, the capital of north Khorasan Province, Iran, in 2016-2017.

In a population-based study, of 6600 children who went to kindergartens in Bojnurd for visual screening, a total of 1100 (three to sixyears of age, the mean age 4.21±1.08 years) children were evaluated who were suspected of having visual problems. Complete eye examinations included visual acuity measurement, cycloplegic refraction (cyclopantolate 1%), subjective refraction and cover test were performed for all participants.

The prevalence of strabismus was recorded as 0.36%. There were no associations of strabismus with age and genders (p>0.05). The most type of strabismus was esotropia. A total of 4.1% of children with strabismus had astigmatism. The prevalence of heterophoria in 1100 children was 22.9%   and the most common heterophoria was exophoria (19.4%). A total of 31.5% of children with myopia had exophoria. However, this rate was lower in children with emetropia (19.09%) and hypropia (16.4%). A total of 1.3% of visual impairments in these children were due to strabismus.

Given the prevalence of strabismus, early diagnosis and treatment at young ages can prevent future visual impairments in these children. Using these findings in planning for children's screening can improve optometric services.