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Proceedings Paper

Theoretical considerations and measurements for phoropters
Author(s): Jiyan Zhang; Wenli Liu; Jie Sun
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Paper Abstract

A phoropter is one of the most popular ophthalmic instruments used in current optometry practice. The quality and verification of the instrument are of the utmost importance. In 1997, International Organization for Standardization published the first ISO standard for requirements of phoropters. However, in China, few standard and test method are suggested for phoropters. Research work on test method for phoropters was carried out early in 2004 by China National Institute of Metrology. In this paper, first, structure of phoropters is described. Then, theoretical considerations for its optical design are analyzed. Next, a newly developed instrument is introduced and measurements are taken. By calibration, the indication error of the instrument is not over 0.05m-1. Finally, measurement results show that the quality situation of phoropters is not as good as expected because of production and assembly error. Optical design shall be improved especially for combinations of both spherical and cylindrical lenses with higher power. Besides, optical requirements specified in ISO standard are found to be a little strict and hard to meet. A proposal for revision of this international standard is drafted and discussed on ISO meeting of 2007 held in Tokyo.

Paper Details

Date Published: 13 October 2008
PDF: 6 pages
Proc. SPIE 7129, Seventh International Symposium on Instrumentation and Control Technology: Optoelectronic Technology and Instruments, Control Theory and Automation, and Space Exploration, 712903 (13 October 2008); doi: 10.1117/12.807368
Show Author Affiliations
Jiyan Zhang, National Institute of Metrology (China)
Beijing Institute of Technology (China)
Wenli Liu, National Institute of Metrology (China)
Jie Sun, National Institute of Metrology (China)


Published in SPIE Proceedings Vol. 7129:
Seventh International Symposium on Instrumentation and Control Technology: Optoelectronic Technology and Instruments, Control Theory and Automation, and Space Exploration

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