Mask configured to maintain nutrient transport without producing visible diffraction patterns

A mask configured to be implanted in a cornea of a patient to increase the depth of focus of the patient, the mask comprising:

• an anterior surface configured to reside adjacent a first corneal layer;
• a posterior surface configured to reside adjacent a second corneal layer;
• an aperture configured to transmit along an optic axis substantially all incident light and a substantially opaque portion surrounding at least a portion of the aperture;
• and
• a plurality of nutrient flow paths extending at least partially between the anterior surface and the posterior surface, the plurality of flow paths being configured to substantially eliminate diffraction patterns visible to the patient and wherein the plurality of flow paths is configured to reduce depletion of at least one biological substance in adjacent tissue of at least one of the first corneal layer and the second corneal layer.