| 摘要 |
PROBLEM TO BE SOLVED: To allow recovery of eye adapting force by forming an image of a given indicator as a virtual image, showing it to an eye to be detected, and changing a showing distance between the eye to be detected and an indicator image forming position. SOLUTION: A light source constituted movably along a light axis integrally with an indicator 1 irradiates the indicator 1. Light from the indicator 1 is transmitted into an eye 3 to be detected via a lens 2 having a positive refracting power. In this case, for example, focal length of the lens 2 is about 250 mm, and distance between the lens 2 and the eye 3 to be detected is about 200 mm. Distance between the indicator 1 and the lens 2 is about 236.05 mm for far view, and is about 63.2 mm for close view. In the case of far view, a virtual image 4 of the indicator 1 is shown to a position about 50000 mm before the eye 3 to be detected, and is observed by the eye 3 to be detected. In the case of close view, the virtual image 4 of the indicator 1 is shown to a position about 300 mm before the eye. Several minute far view and close view observations are repeated. This can recover eye adapting force. |
