A mask configured to be implanted in a cornea of a patient to increase the
depth of focus of the patient includes an anterior surface, a posterior
surface, and a plurality of holes. The anterior surface is configured to
reside adjacent a first corneal layer. The posterior surface is
configured to reside adjacent a second corneal layer. The plurality of
holes extends at least partially between the anterior surface and the
posterior surface. The holes of the plurality of holes are configured to
substantially eliminate visible diffraction patterns.