The optimal refraction after lens implantation is a slight simple myopic astigmatism for patients wishing to see without glasses. The depth of focus is increased in myopic astigmatism because the shape, rather than the size, of the blurred retinal image changes as Sturm's conoid moves over the retina. Such a refraction can be obtained in pseudophakia if the corneal power change induced by surgery is taken into consideration when the intraocular lens. The induced corneal ametropia is a spherocylinder with a very low equivalent power. The results in a series of 50 successive implants employing these principles are described. The depth of fucus is best in simple myopic astigmatism.