Ophthalmic glass

In ophthalmic glass production, the cerium-titania complex is combined with manganese to produce the pink U. V. absorptive tinted glasses. The manganese which normally gives a purple color is toned down with the yellow color giving a yellowish pink. In addition, the cerium absorption in the U. V. is an important property of the glass. 

The free world market for cerium-oxide based polishing compounds is not large—approximately 4400 metric tons per year—, and we do not see a substantial growth potential despite the 11% annual growth in sales of spectacle lenses. The reason is twofold first, faster more efficient polishing compounds are available which can be used in slurry concentrations one-half that of a few years ago second, fully half the market for ophthalmic glass lenses has been captured by plastic lenses of CR-39 polymer. Cerium oxide is ineffective in polishing this material specially treated alumina or stannic oxide are used. 

This survey of organic photochromic and thermochromic compounds focuses on the main families that are involved in existing commercial applications, such as variable optical transmission materials (ophthalmic glasses and lenses), or in potential uses such as optical storage (optical disks or memories). 

Goldman, M. and Yaniv, S.S., Naturally occurring radioactivity in ophthalmic glass. In Radioactivity in Consumer Products, pp. 227-240, NUREG/CP-OOOl, 1978. 

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