A module for use with a mobile device to measure an aberration of a patients eye includes a light shaft having a proximal end and a distal end. The light shaft includes a first plurality of optical components arranged to direct light along a first light path to the proximal end, and a second plurality of optical components arranged to direct light along a second light path to the distal end. A connector at the distal end includes at least one guide component for positioning the distal end adjacent to a light detector and a light source of the mobile device. When the distal end is positioned adjacent to the light detector and the light source, the first plurality of optical components directs light along the first light path and the second plurality of optical components directs light along the second light path.
