An inexpensive, easy-to-use self-refracting device which adjusts to continuously variable prescription corrections for a patient. In preferred embodiments specially designed gear arrangements, controlled by control knobs, moves one lens relative to the other or both lenses relative to each other in directions perpendicular to the viewing direction. The patient turns the devices knobs until vision is clearest. Once the patient adjusted the device for best vision, the patients prescription can be read off various scales on the device. The diopter meter, therefore, can be used to easily and quickly screen for refractive error problems by allowing patients to self-adjust power and, if refractive error is present, see for themselves how much better they could see with corrective glasses.
