Ophthalmic Glass Blanks vs Optical Glass Blanks
Ophthalmic glass should not be confused with optical glass blanks. Ophthalmic or eye glass material does not have to compy with the requirements or guidelines set forth in Mil-Std. 174-B. However, ophthalmic lenses can be made out of certain optical glasses listed in the compendium but the benefit would be minimal and the costs would be substantial higher in most cases.
There is an entire family of glass types that has been developed just for eye or ophthalmic industry. The material has been doped to protect the eyes against UV exposure, the composition has been formulated for chemical or heat strengthening to increase its safety characteristics, and light weight/high index glasses have been developed to reduce the thicknesses of lenses for cosmetic reasons.
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