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, and a light source. The light shaft includes a first plurality of optical components arranged to direct light along a first light path from the light source to the proximal end, and a second plurality of optical components arranged to direct light along a second light path from the proximal end to a light detector of the mobile device. A connector at the distal end includes at least one guide component for positioning the distal end adjacent to the light detector. When the distal end is positioned adjacent to the light detector, 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.
