COMPUTER‐ASSISTED EYE EXAMINATIONS IV. “ADDITIVE” LENS SYSTEMS IN EYE REFRACTORS
作者:
Maxwell Lang,
Elwin Marg,
期刊:
American Journal of Optometry and Physiological Optics
(OVID Available online 1975)
卷期:
Volume 52,
issue 8
页码: 533-540
ISSN:0093-7002
年代: 1975
出版商: OVID
数据来源: OVID
摘要:
After a brief introduction to the optical principles and terms, formulas are derived which de monstrate that with conventional methods and designs it is not possible to summate with accuracy the labeled power of three or more ophthalmic lenses in tandem. The effective power of sphero-cylindrical combinations in all currently available eye refractors, when powers of eight to ten diopters are exceeded, may differ from the summated labeled power by a quarter diopter or more, which can be clinically significant This error can be directly and readily eliminated only in computer-actuated refractors by including a computer program which calculates the effective power and makes the necessary correction.
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