Planned myopic astigmatism as a substitute for accommodation in pseudophakia

Abstract

Patients with an implanted intraocular lens can be made nearly spectacle independent by increasing the depth of focus of the uncorrected implanted eye. In simple myopic astigmatism the visual acuity can be above 20/50 from far to near because the size of the blurred retinal image changes less than its shape as an object approaches the eye. For simple myopic astigmatism the change in corneal power must be included in the calculation of intraocular lens power. The change in corneal power induced by surgery is a spherocylinder with no spherical equivalent. The postoperative shape of the cornea can be predicted and intraocular lens power is calculated to make the flatter meridian emmetropic. The stronger meridian of the cornea is then myopic. In a series of 40 successive cases, the refractions and the measured depth of focus illustrate the application of these principles and the advantage of myopic astigmatism for the pseudophakic patient.