A Polycarbonate Ophthalmic‐Prescription Lens Series
作者:
JOHN DAVIS,
期刊:
American Journal of Optometry and Physiological Optics
(OVID Available online 1978)
卷期:
Volume 55,
issue 8
页码: 543-552
ISSN:0093-7002
年代: 1978
出版商: OVID
关键词: polycarbonate lenses;prescription-lens design;lens aberrations;impact resistance;ANSI Z-80 standards;scratch resistance
数据来源: OVID
摘要:
Improvements in polycarbonate material, production techniques, and scratch-resistant coatings, combined with a process-oriented design, have resulted in a precision lens series. Surface quality is comparable to that of untreated glass ophthalmic lenses. The repeatability of the process results in closely controlled axial power and off-axis performance. For most lens prescriptions, the ANSI Z80.1 optical-center specifications for prescription accuracy are maintained through a total field of view of 40 deg for an 8-mm range of center-of-rotation distances. Off-axis astigmatism is controlled for near-point seeing. The lenses are both lighter and thinner than those of crown glass. A scratch-resistant coating reduces the reflections normally associated with high-index (1.586) materials. Impact resistance exceeds that required by ANSI Z80.7 and is many times that required by ANSI Z80.1.
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