Ocular examination
All examinations were performed by ophthalmologists with 2-4 years of clinical experience using both instruments registered in the unit per the manufacturers’ instructions. Spherical equivalents were calculated by adding the sum of the sphere power with half of the cylinder power obtained by the Topcon RM-A7000B instrument. The spherical equivalents were as follows: Emmetropia was between -0.50 D to + 0.50 D; myopia was < - 0.50 D; Hyperopia was > + 0.75 D. Axial length, anterior chamber depth, central corneal thickness, keratometry, and lens thickness were measured by Lenstar LS 900 instrument. Kmean shows the arithmetic mean of K1 and K2 values.
Baseline parameters of age, gender, height, body mass index (BMI), spherical equivalents (SE), axial length (AL), anterior chamber depth (ACD), central corneal thickness (CCT), keratometry (Kmean), and lens thickness (LT) were analyzed and were compared both annually including the final data. The baseline data belonged from 2013-year and the final data belonged from 2015-year. In this study, the ”onset datum” was defined as the corresponding parameter when children came first to time to the hospital. Accordingly, the onset age was defined as the age when children came first to time to the hospital.