Abstract
Abstract: :
Purpose: To investigate the correlation between subjective refraction and biometry obtained by Orbscan and biometric A-scan echography in normal eyes. To compare biometric parameters according to the subjective spherical equivalent. Methods: Subjective refraction, and biometric parameters using Orbscan and echography were measured in 190 normal eyes (including eyes with ametropia) of 95 patients. Biometric parameters (i.e., corneal diameter, anterior chamber depth, central pachymetry, iridocorneal angle, corneal and crystalline radii of curvature, and axial length of the eye) were compared in different refractive groups and were correlated with subjective refraction. Results:Corneal biometric parameters did not correlate with subjective spherical equivalent and showed no differences between refractive groups except for the central pachymetry. In the high myopia group (<-6D), the central cornea was significantly thinner (531µm versus 549 µm; p=0.016). Correlation between corneal radius of curvature and axial length was high in the emmetropic eyes (rs=0.63 p<0.001) and low but significant in the ametropic eyes (rs=0.28 p=0.002). Axial length, anterior chamber depth, and iridocorneal angle showed significant differences between refractive groups (p<0.001) and correlated with subjective spherical equivalent (rs≷ 0.44 p<0.001). Subjective spherical equivalent showed the strongest correlation with the axial length of the eye (rs=0.82 p<0.001). Conclusion: Biometric characteristics of the eye (excluding corneal characteristics) vary with subjective spherical equivalent. Axial length presents the strongest correlation with the subjective spherical equivalent and correlates with the other ocular biometric parameters. Axial length is of significant influence in ocular biometry and refraction.
Keywords: 542 refraction • 432 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 369 cornea: clinical science