| 摘要 |
PROBLEM TO BE SOLVED: To enhance the operability of an optometer so that the position of the eye to be examined can be recognized and determined over a wide range. SOLUTION: During refractometry, distance is adjusted by focusing cornea- reflected images 4', 5', and axial alignment is achieved by means of an image P' of the pupil. Generally, the distance deviates greatly from the proper range at the beginning, and therefore a diaphragm 9 is inserted to allow recognition of the cornea-reflected images 4', 5' and is driven three-dimensionally to achieve focusing and to bring it to a predetermined position on a screen. Once focusing is achieved to some extent, the diaphragm 9 is moved out of an optical path. This brightens an optical system, allowing the image P' of the pupil to be projected well and facilitating recognition for computations. The edge of the pupil is recognized from the image by use of a computation means and the center position of the pupil is calculated; further, drive for positioning is effected so that the cornea-reflected image 4' is in focus and so that the center of the image P' of the pupil is aligned with the optical path.
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