Abstract

Background: Refractive error is a complex interaction of the biometric parameters depending on both genetic and environmental factors. The amplitude of accommodation (AA) varies with refractive error, and hence, changes in biometric parameters on accommodation also vary with refractive status. Aims and Objectives: The objective of our study was to find out the relationship between various refractive errors and biometric parameters. We also compared the changes in the biometric parameters during accommodation in different refractive states.
Materials and Methods: Our study included 126 subjects of both the sexes. The patients included were between 12 and 35 years of age. The patients were categorized into three groups based on spherical equivalent refraction (SER). SER was calculated by adding spherical refraction and half of cylindrical refraction. Patients with SER ≤±0.5 D were categorized as emmetropia, with SER ≥+0.5 D were categorized as hypermetropia, and patients with SER ≥−0.5 D were categorized as myopia. Various biometric parameters were measured by Nidek echo scan US 800 A - scan biometer for both distant and near focus.
Results: There were 51 myopic subjects: 37 emmetropes and 38 hypermetropes. The axial length and anterior chamber depth were found to be highest in myopes followed by emmetropes and lowest in hypermetropes. On accommodation, the changes in biometric parameters occurred maximally in myopes (P < 0.005), and minimal changes were documented in hypermetropes. Conclusion: We concluded that there exists a strong association between the status of refraction and biometric parameters. There also exists a positive correlation between AA and changes in biometric parameters. The axial elongation in myopes during near work suggests a possibility that near work can lead to development and progression of myopia.