Calculation of an IOL from the wide-angle optical model of the eye

Currently used paraxial formulas for calculating the power of an intraocular lens (IOL) ignore the pupillary aperture of the eye (3.5 mm) and assume that the locations of the principal planes of the crystalline lens and cornea are known. For calculating IOL performance, only the axial point in the field is considered. The eccentricity of the ocular optical system and the probable error in the IOL centering are also ignored. The use of a wide-angle optical model of the aphakic eye for computation of the IOL would result in values that approach more closely those in the real eye. The performance of the implanted IOL could then be calculated in conditions that are much closer to reality. To obtain information on the precision required in preoperative measurement of the asphericity of the cornea, we have studied the effect of corneal asphericity on IOL performance.