US PATENT SUBCLASS 351 / 233
.~.~ Lens or filter selectively insertable in optical path

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

200  DF  EYE EXAMINING OR TESTING INSTRUMENT {7}
222  DF  .~ Subjective type {7}
233.~.~ Lens or filter selectively insertable in optical path {2}
234  DF  .~.~.~> Mounted on rotatable disc {1}
236  DF  .~.~.~> Movable along optical axis

DEFINITION

Classification: 351/233

Lens or filter selectively insertable in optical path:

(under subclass 222) Subject matter wherein the instrument includes selective lenses or spectacle frames carrying lenses of different power movable into and out of eye testing position until errors of refraction are determined, proper lenses have been found and/or corrected vision is obtained.

SEE OR SEARCH THIS CLASS, SUBCLASS:

216+, for movable lens selectively insertable in optical path.

227+, for trial frames.