Abstract: An instrument to perforate ocular tissue can include a handle configured to be grasped by a user, the handle including a proximal handle end and a distal handle end and a dissection cannula configured for at least partial insertion into a patient eye, wherein the dissection cannula can include a proximal cannula end configured to interface with the handle, a distal cannula or trephine end including an opening into a cannula bore, and an indicator spaced from the distal cannula end at a spacing to indicate or control insertion depth of the distal cannula end into the eye.