A Comparative Study of Refractive Errors with Age Related Cataract and Biometric Parameters

Background: The refractive errors such as myopia and hypermetropia are greatly influenced by the cataract morphology and its biometric parameters such as axial length and corneal curvature. This study aims to determine the correlation between the refractive errors, cataract and the biometric parameters of cataract like axial length and corneal curvature. Materials and methods: This cross sectional study was carried out in a tertiary care centre. Hundred patients diagnosed with cataract were recruited for this study. The corneal curvature was measured by keratometry and axial length by A-scan ultrasonography. Cataract was classified as nuclear sclerosis and cortical cataract based on slit lamp examination, and refraction was done by autorefractometer. Results: The prevalence of myopia was considerably more among the subjects than hyperopia. There was a significantly higher prevalence of myopia in nuclear cataract. Most of the subjects with nuclear cataract were associated with myopia, and a small minority with hyperopia. Majority of the patients with cortical cataract were hyperopic. There was an increase in index myopia with increasing nuclear sclerosis. Axial and curvatural myopia account for the rest of the subjects. Axial and curvatural hypermetropia were seen in less number of subjects. Conclusion: Increase in nuclear sclerosis (index myopia) accounts for the majority of myopia. Increase in axial length (axial myopia) and increase in corneal curvature (curvatural myopia) are other determinants of myopia in patients with cataract. Similarly, hyperopia was mostly index, followed by axial and curvatural varieties.