A wearable ophthalmic device is disclosed. The device may include a head-mounted light field display configured to generate a physical light field comprising a beam of light. The head-mounted light field display may direct the beam of light into a user's eye, thereby producing a retinal reflex. The device may also include a head-mounted photodetector array configured to receive the retinal reflex and to generate numerical image data. The device may also include a light field processor configured to control the light field display, to analyze the retinal reflex using the numerical image data, and to determine an optical prescription for the user's eye based on the analysis of the retinal reflex.