Distribution of Different Corneal Topography Patterns in Iranian Schoolchildren: The Shahroud Schoolchildren Eye Cohort Study.

Abstract

OBJECTIVES To determine the distribution of corneal topography patterns (CTPs) in children aged 6 to 12 years and its association with the central corneal thickness (CCT), axial length (AL), mean corneal power (MCP), and corneal astigmatism (CA). METHODS In this population-based study, 5,620 children selected through random stratified cluster sampling were examined. After applying the inclusion criteria, 4,655 right eyes were analyzed. The Pentacam was used to determine the CTP and measure CA and MCP, and the BioGraph was used to measure the AL. Corneal topography patterns were classified based on the 10 patterns proposed by Rabinowitz et al. RESULTS:: The most common pattern in the right eye was the oval pattern [32.7%, 95% confidence interval (CI): 30.9-34.5] followed by asymmetric bowtie with superior steepening (AB-SS) (14.5%, 95% CI: 13.3-15.7), whereas the rarest patterns were AB with skewed radial axis (AB-SRAX) (0.1%, 95% CI: 0.0-0.2) and irregular pattern (0.2%, 95% CI: 0.1-0.4). The similarity between the two eyes was 23.2% (95% CI: 20.9-25.7). The mean CCT was significantly higher in AB-SS than inferior steepening (IS) (P=0.023), symmetric bowtie with SRAX (SB-SRAX) (P=0.030), and AB with IS (AB-IS) (P=0.015). Corneal astigmatism was higher in SB-SRAX compared with round and oval patterns (P value for both <0.001). The AL was greater, and the MCP was lower in the oval versus the SB-SRAX pattern (P value for both <0.001). CONCLUSION The distribution of CTP was different in children and adults, and the oval and AB-SS patterns were the most common CTPs in the current study.