Distribution Pattern of Refractive Errors in Strabismic Iranian Children

The purpose of the present study was to determine the refractive profile of strabismic children under 8 in a tertiary referral center in Tehran, Iran.

This retrospective cross-sectional study was conducted on the medical records of 357 patients under the age of 8 who had one type of strabismus in Farabi Hospital, Tehran, Iran, between 2015 and 2019. All routine ophthalmic examinations were done for all patients. Cycloplegic refraction was performed after the instillation of two drops of cyclopentolate 1% with an interval of 5 minutes, and the refractive error was measured after 30 minutes. The diagnostic criteria were based on cycloplegic refraction in which myopia, hyperopia, and astigmatism were defined when the refractive error was -0.25, +0.75, and -0.50 diopter (D) or more, respectively. The cycloplegic results were classified into different groups with an interval of 1.00 D, and astigmatism was also assessed separately.

In this study, the most common type of refractive error in esotropic patients was hyperopia, with the +2.00 to +4.00 D range having a higher prevalence. In exotropic patients, hyperopia was also prevalent; the most common range of hyperopia was between +0.75 to +1.00 D. Astigmatism had a prevalence of 37.8% in esotropic patients, and 17.2% in exotropic patients with the most common range from -0.50 to -1.00. Myopia was present in 2.8% of patients with esotropia and 3.2 % of patients with exotropia with the most common range from -0.25 to -1.00.

In strabismic Iranian children, hyperopia was the most prevalent refractive error in both esotropic and exotropic patients, with higher degrees of hyperopia in esotropic patients. Low astigmatism was twice as prevalent in patients with esotropia as in patients with exotropia. Low myopia was the least prevalent in both esotropic and exotropia.