OCULAR BIOMETRIC PARAMETERS AND THEIR RELATIONSHIP WITH AGE, GENDER, REFRACTION AND BODY MASS INDEX IN HEALTHY GHANAIAN CHILDREN.

Abstract

Background Ocular biometry involves measurement of axial length, keratometry-value (K-value), anterior chamber depth, lens thickness, and vitreous chamber depth. These biometric values are of importance in clinical decision making in paediatric cataract surgeries, diagnoses of myopia, paediatric laser surgeries and others. Currently, values used in our clinical setting are based on research from other parts of the world. This is due to the dearth of normative data for ocular biometric values for the Ghanaian paediatric population. Published data on paediatric ocular biometry exist abundantly for other populations, however, there is a dearth of published data on this topic in sub-Saharan Africa. This necessitates the need to establish the normative ocular biometric value in the Ghanaian population to optimise our clinical decisions. Aim The study was carried out to determine ocular biometric parameters and their relationship with age, gender, refraction, and body mass index(BMI) in normal Ghanaian school children in the Ablekuma South sub-Municipality.

Materials and methods This was a prospective cross-sectional study which measured the ocular biometric values, refraction, and BMI of Ghanaian school children aged 6 to 15 years in the Ablekuma South sub-Municipality.. Informed written consent was obtained from parents/ guardians and assent obtained from children aged 8 years and above. Children with normal eye exam and no history of known eye disease were included in the study. An interviewer-administered pre-designed questionnaire was used to record demographic data such as age, sex, ethnic origin, data on ocular biometric measurements (axial length, anterior chamber depth, lens thickness, vitreous chamber depth,keratometry-value, and cornea radius), and outcome of cycloplegic refraction.

Data handling and statistical analysis The data was analysed with SPSS version 25. Descriptive statistics were performed for demographic and ocular biometric parameters and results presented with appropriate charts and and tables. Relationship between ocular biometric parameters and demographic and anthropometric factors were assessed with the independent t-test for differences in continuous variables, analysis of variance (ANOVA) for differences between groups such as age and gender and linear regression for differences in trends. Statistical significance was set at a p- value of less than 0.05.

Results Data on 352 children were analysed (704 eyes). They were aged 6 to 15 years, with 55% being female and 45% being male. They had a mean axial length of 22.73±0.75mm, anterior chamber depth of 3.28±0.29mm, lens thickness of 3.65±0.27mm, vitreous chamber depth of 19.44±0.70mm, cornea radius of 7.79±0.28mm and K-value of 43.39±1.56D. Axial length was 22.99±0.78mm in males and 22.51±0.69mm in females; anterior chamber depth was 3.34±0.32mm in males and 3.34±0.21mm in females; vitreous chamber depth was 19.66±0.78mm in males and 19.27±0.58mm on females; and cornea radius was 7.85±0.32mm in males and 7.74±0.20mm in females. K-value was 43.65±1.61D in females compared to 43.06±1.38D in males. Axial length (p=0.001, F=9.366), anterior chamber depth (p=0.001, F=6.447) and vitreous chamber depth (p=0.001, F=5.937) increased with increasing age. Cornea radius (p=0.644, F=0.556) and lens thickness (p=0.379, F=1.030) did not increase significantly with increasing age. Axial length (p=0.001, r=0.281), anterior chamber depth (p=0.001, r=0.228) and vitreous chamber depth (p=0.029, CI=0.01-0.11) had a significant positive relationship with BMI. Axial length (p=0.007, CI=0.00-0.20), anterior chamber depth (p=0.004, CI=0.00-0.20) were significantly related to hyperopia. while myopia and emmetropia had significant relationships with axial length, anterior chamber depth and vitreous chamber depth

Conclusion Ocular biometric parameters increased with age, higher in males compared to females. There was a positive relationship between ocular biometry and BMI. Ocular biometry positively correlated with myopia and negatively correlated with hyperopia. Results from this study were similar to that from other studies conducted in sub-Saharan Africa. The findings could support future large population-based study on ocular biometric parameters in the paediatric population to help in the diagnosis and management of serious eye diseases.