A portable device for the measurement of refractive error in the eye is disclosed. The device generally includes a liquid lens that the patient looks through, a projective array of static lenses, an electronic display, a system of electronics, and software that controls the potential applied to the liquid lens, controls the display, and runs the algorithm that processes patient feedback in order to determine the correct corrective lens powers. Housed in a singular body that can be held and positioned in front of the patient's eye, the device allows direct feedback and interaction by a patient using a remote control. Altogether, the device is automatically determines a voltage of the liquid lens that provides the patient with the clearest vision, which can be used to calculate the prescription corrective lens power.
