US PATENT SUBCLASS 351 / 164
.~.~.~ Multifocal

Current as of: June, 1999
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351 /   HD   OPTICS: EYE EXAMINING, VISION TESTING AND CORRECTING

41  DF  SPECTACLES AND EYEGLASSES {29}
159  DF  .~ Ophtahalmic lenses or blanks {10}
163  DF  .~.~ With light filtering means {2}
164.~.~.~ Multifocal

DEFINITION

Classification: 351/164

(under subclass 163) Subject matter wherein multifocal lenses absorb certain portions of rays in the visible or invisible spectrum, or are combined with additional structure having such an absorption property.

SEE OR SEARCH THIS CLASS, SUBCLASS:

168, for multifocal lenses generally.