Residual astigmatism produced by toric intraocular lens rotation.

Purpose To analyze changes in the eye’s refractive properties when a toric intraocular lens (IOL) rotates. Setting Fundacion Oftalmologica del Mediterraneo, Valencia, Spain. Design Experimental study. Methods The matrix definition of astigmatism was used in this theoretical study and compared with another vector representation. Two methods were compared: (1) The cylinder, C, resulting from the addition of 2 cylinders C1 and C2 whose axes form an angle a, is obtained by the addition of 2 vectors of values C1 and C2 forming an angle 2a; (2) the power matrix, F, of a thin astigmatic dioptric system that decomposes naturally into 3 orthogonal components: the purely spherical part Fnes, the orth…