Relationship Between Keratoconus and Axial Myopia

Abstract

Abstract: : Purpose: To study the relationship between keratoconus and axial myopia. Methods: We prospectively studied refraction and ocular biometry in 50 consecutive keratoconic eyes and 50 emmetropic eyes. Biometric data (including posterior segment length, corneal radius of curvature) were obtained by echography, Orbscan, and ultrasonic pachymetry. Keratoconus were classified using Amsler classification. The origin of myopia (corneal or axial) in the keratoconus group was determined using the regression between vitreous length and corneal radius of curvature in the emmetropic group. Results: The posterior segment length is significantly greater in the keratoconus group than in the emmetropic group (16.78 mm versus 16.03 mm p< 0.001). Posterior segment length shows no significant correlation with corneal ectasia parameters (corneal radius of curvature, pachymetry, and Amsler classification; p>0.10).In the keratoconus group, the cornea is responsible for 60% of the myopia in stade 1 or 2, 78% in stade 3, and in 91% in stade 4. Conclusions: Keratoconus present a significant relationship with axial myopia.

Keywords: keratoconus • myopia • vitreous