An apparatus and method for suture fixation. A digital image is accessed and segmented, and a first histogram of the digital image is generated. The refractive structures are written by irradiating select regions of the cornea tissue with focused laser pulses having a wavelength from 400 nm to 900 nm and a pulse energy from 0. After a space between the mold and the inner tube has been filled with the molten second material, a first thermal gradient develops between the inner tube and the mold, a second thermal gradient develops between the bottom and the top of the mold, and the outer tube is simultaneously cooled from the inside to the outside and from the bottom to the top.