An exact skew-ray-tracing method for theoretically predicting the power of intraocular lenses

Computer-simulated anatomically exact optical skew-ray tracing is used as a new method of predicting the power required for intraocular lenses. This method predicts the post-operative refractive power of the eye according to the results of preoperative measurements, that is, the curvature or the anterior and posterior cornea surfaces, the thickness and width of the cornea, the thickness and the curvature of the anterior and posterior surfaces of the intraocular lens, and the axial length of the eye. It is experimentally shown that the new method performs better than SRK/T and SRK-II, which are currently in widespread use as calculation formulae in clinical ophthalmology. Namely, the mean absolute refractive error of the method assessed in the feasibility study (N=10) is 0.2928 +/- 0.2453 diopter (D), where the equivalent errors are 0.4790 +/- 0.3385 D for SRK/T and 0.9174 +/- 0.4053 D for SRK-II. The new method uses an exact model of anatomical structure and can accurately simulate the path of light rays in the eye, while SRK-II/T relies on certain experimental modifications, abbreviations of formulae, and approximations of parameters.