[A new application of the ray tracing error correction (RTEC) method to ophthalmic optics]

The theory and procedures of the ray tracing error correction method (RTEC) which performs various refractive calculations in ophthalmology is explained. Calculations for the different corrective methods; i.e. glasses, contact lens, refractive corneal surgery and IOL are determined in the same manner without any simplification or approximation of the optical model. RTEC consists of two procedures; a ray tracing determining whether the ray originating from infinity focuses on the fovea, and an error correction formula that varies the curvature of the glasses, cornea or IOL when the ray is not focused at the fovea. These calculations are continued until the values for the ray focused at the fovea are obtained. The refraction of Helmholtz' schematic eye at relaxation and at accommodation, the desired postoperative corneal curvature with a -2D postoperative refraction and 28 mm axial length, and the IOL power determination with -2D postoperative refraction and 24 mm axial length are presented.