*** Warning: only usable by opticians / optometrists! *** The UbiVision Eyechart / Optotype App displays optotypes to perform a subjective refraction by an optician / optometrist. * flexible text distances from 1 to 6 meters (3 to 18 feet) * Notation System in 20/xx or Decimal * remotely controllable by iPhone Optotypes shown: * Snellen Letters * Sloan Numbers * Sloan Letters * Landolts Rings * Tumbling E's Optotypes will display on an iPad, remotely controlled by an iPhone. And also there is a Near Vision Test.