Smart phone based virtual visual charts for measuring visual acuity

A method for adjusting sight lines from an image produced by screen such that the adjusted sightlines replicate the sightlines perceived by an optical system viewing a physical eye chart, the method comprising the steps of:

• a) using a first lens in visual communication with an image presented upon a display screen, wherein the first lens demagnifies the image presented upon the screen;
• wherein the first lens uses an aspherical surface that is proximal to the display screen and wherein the first lens uses a concave surface that is distal to the display screen;
• b) using a second lens in visual communication with the first lens, wherein the second lens magnifies the demagnified image sent by the first lens;
• c) presenting the magnified image from the second lens to an end user;
• and
• d) using a deformable adjustable lens system to form a phoropter device, allowing estimates of the user's refractive error in each eye, the deformable adjustable lens system disposed between a user's eye and the second lens.