9 OPHTHALMIC LENSES AND FRAMES, PROTECTIVE GLASSES AND LENSES THEREFOR; MATERIALS AND DEVICES USED BY OPTOMETRISTS AND OPHTHALMOLOGISTS FOR THE EXAMINATION AND CORRECTION OF VISION-NAMELY, FOCOMETERS, PUPILMETERS, KERATOMETERS, SKIASCOPES, READING SCALES, REFRACTING CHART PROJECTORS AND REFRACTOR COLUMNS