Postoperative computer refraction of implant patients

Abstract

The formula used to calculate the intraocular lens (IOL) power for emmetropia contains the following variables: the refracting power of the cornea, the axial length, and the anterior chamber depth. The formula was expanded to contain a fourth variable, the desired refraction, to calculate the IOL power required to achieve this refraction [1]. The latter formula is more useful in preoperative IOL power calculation than the formula for emmetropia because emmetropia is usually not the goal. One may aim at a different refraction, e.g. to match a fellow eye with good vision, while in general one aims at a small amount of myopia to compensate for the lack of accommodation in the artiphakic eye and to avoid an error on the hyperopic side.