Catalogue Number: 570
The Standard (Culbertson) Prisoptometer
Designer/inventor: The Standard Optical Company
Year Of Publication/Manufacture: 1904
Time Period: 1900 to 1939
Place Of Publication/Manufacture: Geneva, New York
Publisher/Manufacturer: The Standard Optical Company
Description Of Item: Dimensions: 58cm H x 21cm W. Made of: cast iron, steel, brass, glass. Imprinted: THE STANDARD PRISOPTOMETER/ STANDARD OPTICAL COMPANY MAKERS, GENEVA, N.Y. PATENTED JUNE 21, 1904. Stamped:' 263' on eyepiece and '2' on rear of eyepiece and base.The instrument includes a prism, which can be rotated, and was used to view a disc or object circle. The prism caused monocular doubling of the object circle and the separation of the two images as the prism was rotated varied, depending on the astigmatism present. The axis of astigmatism was indicated by the prisoptometer and trial lenses were used to determine the magnitude of the spherical and cylindrical refractive error.
Historical Significance: The Museum holds another example of Dr Culbertson's Prisoptometer, Catalogue Number 202. It is an example of the ingenuity of ophthalmic practitioners at the turn of the 19th C in designing instruments for refraction, but in this instance the device gained little acceptance in the face of the cross cylinder test and the astigmatic fan test.
How Acquired: Donated by Pamela Sutton, VCO honorary archivist
Date Acquired: 3.03.2008
Location: Archive room. West wall. Unit 3 Overhead display