# Correlation of Ocular Biometric Characteristics and Central Corneal Thickness With the Severity of Myopia: A Multicentric Study From Bodhya Eye Consortium, India

## TL;DR

This study finds that eye measurements like axial length are strongly linked to myopia severity in children, while corneal thickness is not.

## Contribution

The study provides population-specific ocular biometric data for Indian children and identifies key parameters associated with myopia severity.

## Key findings

- Axial length strongly correlates with myopia severity, with longer axial lengths associated with higher degrees of myopia.
- Steeper corneal curvature, reduced anterior chamber depth, and increased lens thickness are independently associated with more severe myopia.
- Central corneal thickness does not show a significant independent association with myopia severity.

## Abstract

Purpose: To evaluate the correlation and independent associations between ocular biometric parameters and central corneal thickness with the severity of myopia in children.

Methods: This multicentric retrospective cross-sectional study included children ≤18 years of age with simple axial myopia or compound myopic astigmatism. Ocular biometry was performed using an optical biometer (IOL master, Zeiss). The data collected was age, gender, height, weight, body mass index (BMI), cycloplegic refraction (Spherical Equivalent, SE), best corrected visual acuity (BCVA), axial length (AL), anterior chamber depth (ACD), lens thickness (LT), corneal power (K), central corneal thickness (CCT), and AL/Corneal curvature (CR) ratio. The various demographic and biometric parameters were compared between the myopia categories [low (≥−3.00 D), moderate (-3.25 to ≥-6.00D), and severe (<-6D)].

Results: A total of 1095 children (2174 eyes), 579 males and 516 females, were included. Out of 1095, 16 patients had one eye myopic while the other was emmetropic. The mean age was 11.61 ± 3.73 years. Low, moderate, and severe myopia was observed in 35.53%, 29.13%, and 35.34% of children with a mean SE of -1.93±0.71, -4.35±0.84, and -10.22±3.70, respectively. The severe myopia group showed the lowest mean values for age, height, weight, BMI, and the poorest mean BCVA (p < 0.001). Axial length demonstrated a strong association with SE, with increasing AL corresponding to higher degrees of myopia (estimate = -2.53, p < 0.001). Steeper mean keratometry (estimate = -1.01, p < 0.001), reduced ACD (estimate = 2.73, p < 0.001), and greater LT (estimate = -1.63, p = 0.001) were also significantly associated with more severe myopia. In contrast, CCT did not show an independent association with SE (p = 0.743). Among demographic variables, height showed a modest but significant relationship, with taller children associated with slightly lower degrees of myopia (estimate = 3.70, p < 0.001). Parental myopia and other covariates did not retain statistical significance after multivariable adjustment.

Conclusion: In this large multicentric cohort of Indian children, ocular biometric parameters, particularly AL, CR, ACD, and LT were independently associated with the severity of myopia. The CCT showed no significant relationship. These findings underscore the importance of comprehensive ocular biometric profiling beyond SE alone for understanding myopia severity. Population-specific biometric data may aid in improved risk stratification and individualised myopia management.