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Proceedings Paper

Plastic photochromic eyewear: a status report
Author(s): John C. Crano; Richard C. Elias
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Paper Abstract

An estimated 10 million pairs of photochromic prescription lenses were dispensed in the United States in 1989, essentially all based on a silver halide system suspended in an inorganic glass. A significant trend within the ophthalmic industry has been the growth of light-weight plastic lenses. In the United States market, the percentage of prescription eyewear made of plastic is now greater than 70%. With this increasing market penetration of plastic lenses, the desire for an acceptable plastic photochromic lens has also increased. As with any commercial product, in order to achieve consumer acceptance there exist several technical requirements for a plastic photochromic lens. These include the light transmission and color of the lens in both the unactivated and activated states, the speeds of darkening and fading, and the fatigue resistance or lifetime of the photochromic system. These requirements will be defined along with approaches to achieving them. The properties of the commercially available plastic photochromic lenses will be compared with the defined requirements.

Paper Details

Date Published: 1 December 1991
PDF: 8 pages
Proc. SPIE 1529, Ophthalmic Lens Design and Fabrication, (1 December 1991); doi: 10.1117/12.50486
Show Author Affiliations
John C. Crano, PPG Industries, Inc. (United States)
Richard C. Elias, Transitions Optical, Inc. (United States)

Published in SPIE Proceedings Vol. 1529:
Ophthalmic Lens Design and Fabrication
Colin M. Perrott, Editor(s)

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