AutoCross for testing for power and axis of astigmatism

Catalogue Number: 2339
AutoCross for testing for power and axis of astigmatism
Category: Equipment
Sub-Category: Equipment, other clinical
Corporation: Tokyo Optical Company
Time Period: 1940 to 1999
Place Of Publication/Manufacture: Tokyo Japan
Publisher/Manufacturer: Tokyo Optical Company (Topcon)
Description Of Item: Cream coloured instrument for measuring axis and power of astigmatism. The instrument is designed to plug into the eye pieces of a phoropter, in this case a Bausch and Lomb phoropter, for making simultaneous comparisons in subjective refraction. It is an image splitting device that produces monocular diplopia so that + and - 0.25 D Cyl views can be compared side by side in one mode. It acts as a cross cylinder test but with simultaneous comparisons of the two images rather than successive. The instrument is contained in the original grey coloured box without markings with an internal lining in white fabric. The instrument is marked AUTO CROSS No 80969 TOKYO KOGAKU. Also in the box is an 8 page instruction booklet.
Historical Significance: Tokyo Optical Co., Ltd is the corporate name for Topcon, a Japanese manufacturer of optical equipment for ophthalmology and surveying. Their headquarters are in Itabashi, Tokyo. They are affiliated with Toshiba, which holds 40% of Topcon's stock. It was founded in 1932 as a surveying instrument company and began making ophthalmic instruments in 1947 and cameras in 1963. This instrument is similar in principle to the ZEISS simultan test (See Cat No 457, 2053, 2054) that was made in c 1968.
How Acquired: Donated by Terry Coyle, member of the College
Date Acquired: Sept 2013
Condition: Very good
Location: Archive room. West wall. Unit 6 Drawer 4

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