Method and apparatus for refraction and vision measurement

Abstract

Consumer products such as refraction measurement devices may be used for obtaining refraction measurements allow consumers to track their vision without visiting an optometrist or ophthalmologist. Such consumer products may work in concert with smart phones or other products having a touch screen that present images to refraction measurement devices. Smart phones may have resolution rates, sometimes measured as PPI or pixels per inch that are unknown to the user and/or refraction measurement device. One aspect of the invention is to provide an optical interface for the user to manually match the view port boundary of the smartphone to comport with the view port boundary of the refraction measurement device. Another aspect of the invention is the use of pre-distortion in images presented to the user. By noting the corrective movements exerted by the user upon the refractive measurement device, the user's own refractive error can be derived.