A, Light striking the edge of the IOL may be reflected to another site on the retina, resulting in undesirable dysphotopsias. These problems arise less often with smoother-edged IOLs. B, Light may be internally re-reflected within an IOL, producing an undesirable second image or halo. Such re-reflection may be more likely to occur as the index of refraction of the IOL increases. C, Light may reflect back from the surface of the retina and reach the anterior surface of the IOL. The IOL acts as a concave mirror, reflecting back an undesirable dysphotopsic image. When the anterior surface of the IOL is more curved, the annoying image is displaced relatively far from the fovea. D, When the anterior IOL surface is less steeply curved, the annoying image appears closer to the true image and is likely to be more distracting.