CLEAR VISION METER
PROBLEM TO BE SOLVED: To solve such a problem that it is difficult to measure an exact distance in a conventional near vision measurement, because a subject judges the point of time when a visual target, such as a Landolt ring, becomes unclear while it is getting closer to the eye. SOLUTION: By usin...
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| Zusammenfassung: | PROBLEM TO BE SOLVED: To solve such a problem that it is difficult to measure an exact distance in a conventional near vision measurement, because a subject judges the point of time when a visual target, such as a Landolt ring, becomes unclear while it is getting closer to the eye. SOLUTION: By using a black film having four pin holes through which disappearance of the visual target is visually confirmed, near vision measurement is easily judged. The measurement is carried out by using a dark filter and switching into three steps in accordance with the degree of near vision. Thus, changes of near vision before and after the treatment of eyestrain or dry eyes, and daily changes of near vision can be checked with a clear vision meter using a portable ultrasonic wave. COPYRIGHT: (C)2009,JPO&INPIT |
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