A process is provided for conducting an eye examination using a mobile device, the process comprising capturing a first image of an object using a camera of a mobile device set to a fixed focusing distance； determining, with reference to the first image, an absolute size of the object； capturing a second image of the object using the camera of the mobile device； determining, with reference to the second image, a distance from the mobile device to the object； providing an indication via the mobile device to move the mobile device relative to the object； and receiving input from the mobile device in response to an eye examination program.
