ophthalmic lens blanks showing the various stages in the manufacture of trifocal lenses
Rest of parts of collection (unspecified) consisting of 24 glass and plastic ophthalmic lenses showing the various stages in the manufacture of trifocal lenses
Rest of parts of collection (unspecified) consisting of 24 glass and plastic ophthalmic lenses showing the various stages in the manufacture of trifocal lenses
