| 摘要 |
The present invention measures a high contrast eyesight and a low contrast eyesight even though two types of visual targets which have different contrast ratios are not prepared. The present invention includes a visual target straight look optical instrument (10) through which a tested eye (E) straightly looks at a part of multiple visual targets (12a) which correspond to a measured eyesight; and a visual light source (11) which radiates illumination to the visual target (12a) at which the tested eye (E) looks straightly by the visual target straight look optical instrument (10). The present invention includes a control unit (100) which performs a process S2 which converts the intensity of illumination which is radiated to the visual target (12a) from the visual light source (11) into a predetermined first intensity and a second intensity which is exposed more than the first exposure; and a process S3 which converts the visual target at which the tested eye (E) looks straightly in case of converting the intensity of illumination, which is radiated from the visual light source (11) to the visual target (12a), from the first intensity into the second intensity. |
