Correlations of anterior and posterior corneal parameters in Chinese myopic patients

Abstract

Abstract Background Whether the correlations between anterior and posterior corneal parameters vary according to different conditions is unknown.Methods A total of 8365 myopic eyes having refractive surgery between 2017 and 2019 from multiple ophthalmic centers were consecutively included in the study. All the eyes underwent routine ocular examinations including corneal Scheimpflug imaging. Pentacam data of the eyes were retrieved from the machine and only results with image quality labelled with ‘OK’ were included. The anterior-posterior correlations of corneal curvature, astigmatism, eccentricity and asphericity were assessed using Spearman’s correlation test by grouping the eyes via different myopic groups and different quantile levels of six corneal and anterior chamber parameters (Sim Km, pachy apex, corneal volume and diameter, anterior chamber height and volume).Results Strongly negative anterior-posterior correlations of the mean corneal curvature were observed, with similar correlation coefficients in all the myopic groups (R: -0.85 to -0.88). The anterior-posterior correlations of corneal astigmatism (R: 0.65 to 0.75), eccentricity (R: 0.27 to 0.38) and asphericity (R: 0.29 to 0.41) were all positive, with the correlation coefficients slightly different between the myopic groups. The anterior-posterior correlations of mean corneal curvature were strongly negative with similar correlation coefficients in all the quantile groups of six corneal and anterior chamber parameters (R: -0.84 to -0.91), except Sim Km (R: -0.36 to -0.64). The anterior-posterior correlations of corneal astigmatism were all positive with the correlation coefficients slightly different between the quantile groups of SimKm (R: 0.66 to 0.74). The anterior-posterior correlations of corneal eccentricity (R: 0.30 to 0.44) and asphericity (R: 0.33 to 0.45) were positive and slightly different between the quantile groups of SimKm, pachy apex and corneal volume.Conclusion The anterior-posterior correlations of corneal curvature, astigmatism, eccentricity and asphericity are affected by the severity of myopia and some other corneal parameters.