A Study on the Relationship between Corneal-Related Value and Ocular Sagittal Height

Abstract

Purpose : To investigate the effect of corneal related values on the ocular sagittal height and which factors have the greatest influence on the ocular sagittal height. Methods : For 240 healthy eyes in their 20, 30, 40, and 50s, the anterior chamber depth and axial length were measured with IOLMaster 700. The corneal curvature radius and corneal eccentricity were measured with Keratograph 4, and spherical equivalent power was measured using KR-800. The corneal sagittal height was calculated using the formula. Results : The most influential factor in the corneal sagittal height was the corneal diameter, followed by the corneal eccentricity. And the corneal curvature radius had the least effect. A change in corneal saggital height of about 0.10mm corresponds to a change in corneal diameter of 0.20mm, and corneal eccentricity of 0.05 to 0.10 Conclusion : If soft contact lens fitting is greatly affected by the relationship between the sagittal depth of the contact lens and the sagittal height of the cornea, measurements of corneal diameter and corneal eccentricity are considered appropriate methods for selecting parameters of contact lenses. In addition, the numerical relationship between corneal sagittal height, corneal diameter and corneal eccentricity could be used as additional information for soft contact lens fitting.