System for conducting eye examinations for visual acuity

A system for conducting an eye examination for visual acuity, comprising:

• an optical subsystem configured to be positioned in front of one or both eyes of a user, the optical subsystem comprising i) a handheld device or ii) a head worn device, a visual indicator having a fixed size, and a plurality of vision modifiers configured to modify vision of the user;
• a camera;
• a display;
• and
• one or more processors configured by instructions stored in memory to:
• determine, via the camera, a distance between the optical subsystem and the display, the distance determined based on comparing the fixed size of the visual indicator to a detected size of the visual indicator in an image obtained by the camera;
• output, via the display, an eye examination image for testing visual acuity based on the distance being within a valid range, the eye examination image including a visual stimulus having an output size determined based on the distance;
• and
• receive an input from the user indicating a selection of the visual stimulus.