Distribution of corneal thickness and its determinants in 6–12-year-old children in an Iranian general population

Abstract

Purpose To determine the central corneal thickness (CCT), apex, and paracentral thicknesses and their determinants in children aged 6–12 years. Methods The present study was part of the phase 1 of Shahroud School Children Eye Cohort Study in 2015. Cluster sampling was done in urban areas while all children were invited to participate in the study in rural areas. The Pentacam HR was used for measurements. CCT was measured within the central 3 mm zone of the cornea, and corneal thickness 3 mm further from the center was considered paracentral thickness. Results Of 6624 students who were selected, 5620 (84.8%) participated in the study. Among 4956 students, studied in this report, 52.2% were boys, and the mean age of the study participants was 9.75 ± 1.71 years (6–12). The mean CCT and apical thickness was 556.29 ± 34.04 and 557.43 ± 34.03 μm, respectively. The mean paracentral thickness was 657.62 ± 39.11 μm in the superior, 632.65 ± 37.63 μm in the inferior, 648.64 ± 38.75 μm in the nasal, and 617.36 ± 37.19 μm in the temporal region. A multiple regression model showed that CCT decreased by 4.70 μm with every 1 diopter increase in the mean keratometry and increased by 20.06 μm with every 1 mm increase in the anterior chamber depth (ACD) (Both P -Value < 0.001). Age, sex, ethnicity and residence place were also found to be associated with CCT. Conclusions This study is the first to describe the distribution of corneal thickness in Iranian children with a large sample size. This study showed that corneal thickness was significantly correlated with younger age, female gender, urban residence, and a number of biometric variables.

Total corneal refractive power and shape in Down syndrome

“…In agreement with our results, several population-based studies have reported sim-Ksteep and sim-Kflat to be approximately 44.0 and 43.0 D in normal samples in this age range (10–30 years). 19–21 Although different devices (Pentacam and Orbscan) have been used in these studies, there is no significant variation among the reported ranges. To the best of our knowledge, no population-based studies have yet reported the reference range of TCRP-based Ksteep and Kflat in patients with Down syndrome or normal subjects.…”