Scientific Instruments > Scientific Optical

Barrett Monocular and Testing Set London Optical Co. Ltd

Item#: SOI1242

Price: $55.00

 

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Barrett Monocular and Testing Set London Optical Co. Ltd - click to enlarge.Barrett Monocular and Testing Set London Optical Co. Ltd - click to enlarge.

This is a set of lenses for testing sub-normal vision. The set contains two rimmed mounted lenses, 6 apertures, framed and with a small handle on which a number is inscribed. 3 apertures have rectangular opening and three have round openings. This test is done to determine if sub-normal vision is due to refractive problems in the eye or to an eye disease. If looking through a round aperture improves the eyesight, than the sub-normal vision is probably due to uncorrected refractive errors and the visual acuity can be corrected with eyeglasses. If however the eyesight is not improved then it is likely that an eye disease is present and should be tended to by a doctor. The set comes in its original purple velvet and silk lined fitted case.