Handheld vision tester and calibration thereof

A calibration system for use with a manual vision screening device (100), having a screen (04), comprising: a reflective surface (204) and characterized by a calibration support (200) configured to support said handheld vision testing apparatus (100), having said screen (104) at a fixed distance from said reflective surface (204), wherein said handheld vision testing apparatus (100) displays images; and the reflective surface (204) is attached to said calibration support and oriented substantially parallel to said display, when the calibration support (200) supports the handheld vision tester (100) at a fixed distance from the reflective surface (204).