GB737654A - Improvements in or relating to sight testing apparatus - Google Patents

Improvements in or relating to sight testing apparatus

Info

Publication number
GB737654A
GB737654A GB2525051A GB2525051A GB737654A GB 737654 A GB737654 A GB 737654A GB 2525051 A GB2525051 A GB 2525051A GB 2525051 A GB2525051 A GB 2525051A GB 737654 A GB737654 A GB 737654A
Authority
GB
United Kingdom
Prior art keywords
letters
sight
polarizing
eyepieces
right angles
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB2525051A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to GB2525051A priority Critical patent/GB737654A/en
Publication of GB737654A publication Critical patent/GB737654A/en
Expired legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
    • A61B3/02—Subjective types, i.e. testing apparatus requiring the active assistance of the patient
    • A61B3/028—Subjective types, i.e. testing apparatus requiring the active assistance of the patient for testing visual acuity; for determination of refraction, e.g. phoropters
    • A61B3/04—Trial frames; Sets of lenses for use therewith
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
    • A61B3/02—Subjective types, i.e. testing apparatus requiring the active assistance of the patient
    • A61B3/028—Subjective types, i.e. testing apparatus requiring the active assistance of the patient for testing visual acuity; for determination of refraction, e.g. phoropters
    • A61B3/032—Devices for presenting test symbols or characters, e.g. test chart projectors
    • G—PHYSICS
    • G02—OPTICS
    • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
    • G02C7/00—Optical parts
    • G02C7/12—Polarisers

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Ophthalmology & Optometry (AREA)
  • Physics & Mathematics (AREA)
  • General Health & Medical Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Biophysics (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Instructional Devices (AREA)

Abstract

737,654. Sight-testing apparatus. LANGTON, F. Jan. 21, 1953 [Oct. 29, 1951], No. 25250/51. Class 97 (1). In sight-testing apparatus the object to be viewed comprises at least two pairs of letters or symbols arranged in rows and covered with sheets of polarizing material so that the light from the letters of each pair is polarized in perpendicular planes and the eyepieces of the sight-testing frame is provided with analysers arranged with their planes of polarization at right angles to one another so that one letter of each row will be obscured when veiwed through one eyepiece and another letter obscured when viewed through the other eyepiece. As shown the apparatus comprises a cabinet 1 having two apertures 17, 18 in the front wall. Mounted behind the aperture 17 are two vertically displaced rollers bearing an opaque band pierced with a series of rows of letters 13, illuminated by lamps within the casing, the rollers being rotated by a knob 12 to change the letters on view. A slide 21 bearing a single piece of polarizing material, or two juxtaposed pieces with polarizing axes at right angles is inserted behind the aperture 17 and the letters 13 are viewed through a sight-testing frame, Fig. 7, bearing two polarizing eyepieces 26, 27 which may be rotated through 90 degrees so that with a single polarizer in the slide 21 sight of the letters 13 by one or other eye may be obscured by rotation of the eyepieces 26, 27, while with two polarizers in the slide the letters seen by each eye may be interchanged by such rotation. Mounted behind the aperture 18 are opaque screens apertured in the form of letters 32, 33, 34, 35 illuminated from the rear, and before each pair 32, 33 and 34, 35 are polarizing screens 36, 37 and 38, 39 arranged to plane polarize light at right angles. Observation is effected with the polarization axes of the eyepieces 26, 27 arranged at right angles to one another. Specification 682,350 is referred to.
GB2525051A 1951-10-29 1951-10-29 Improvements in or relating to sight testing apparatus Expired GB737654A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2525051A GB737654A (en) 1951-10-29 1951-10-29 Improvements in or relating to sight testing apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2525051A GB737654A (en) 1951-10-29 1951-10-29 Improvements in or relating to sight testing apparatus

Publications (1)

Publication Number Publication Date
GB737654A true GB737654A (en) 1955-09-28

Family

ID=10224634

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2525051A Expired GB737654A (en) 1951-10-29 1951-10-29 Improvements in or relating to sight testing apparatus

Country Status (1)

Country Link
GB (1) GB737654A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2514127A1 (en) * 1981-10-01 1983-04-08 Zeiss Jena Veb Carl POLARIZATION OPTICAL DEVICE FOR SWITCHING STEREOSCOPIC OBSERVATION IN PHOTOGRAMMETRIC INTERPRETATION APPARATUS
FR2710515A1 (en) * 1993-09-29 1995-04-07 Sabban Yossef Procedure for measuring the spatial resolution or visual acuity of patients still at a pre-verbal stage, in particular infants, as well as a device for carrying out this procedure

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2514127A1 (en) * 1981-10-01 1983-04-08 Zeiss Jena Veb Carl POLARIZATION OPTICAL DEVICE FOR SWITCHING STEREOSCOPIC OBSERVATION IN PHOTOGRAMMETRIC INTERPRETATION APPARATUS
FR2710515A1 (en) * 1993-09-29 1995-04-07 Sabban Yossef Procedure for measuring the spatial resolution or visual acuity of patients still at a pre-verbal stage, in particular infants, as well as a device for carrying out this procedure

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