GB197147A - An instrument for testing visual astigmatism - Google Patents

An instrument for testing visual astigmatism

Info

Publication number
GB197147A
GB197147A GB875722A GB875722A GB197147A GB 197147 A GB197147 A GB 197147A GB 875722 A GB875722 A GB 875722A GB 875722 A GB875722 A GB 875722A GB 197147 A GB197147 A GB 197147A
Authority
GB
United Kingdom
Prior art keywords
perforations
astigmatism
instrument
newbold
fitted
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
GB875722A
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.)
STANLEY WILLIAM NEWBOLD
Original Assignee
STANLEY WILLIAM NEWBOLD
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 STANLEY WILLIAM NEWBOLD filed Critical STANLEY WILLIAM NEWBOLD
Priority to GB875722A priority Critical patent/GB197147A/en
Publication of GB197147A publication Critical patent/GB197147A/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
    • A61B3/036—Subjective types, i.e. testing apparatus requiring the active assistance of the patient for testing visual acuity; for determination of refraction, e.g. phoropters for testing astigmatism

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Medical Informatics (AREA)
  • Biophysics (AREA)
  • Ophthalmology & Optometry (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Physics & Mathematics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

197,147. Ryland, H. S., Newbold, S. W., and Newbold, P. A. March 27, 1922. Sight-testing apparatus.-For testing visual astigmatism a plate 20 or plane surface provided with one or more straight lines of perforations in the form of squares is used, and is fitted at one end of a casing 9 containing a source of light 12, inserted from beneath, as shown. The plate 20 is rotatable over a disc 21 of opal glass, and may be replaced by other plates having slightly differentsized perforations. The preferred size of the perforations is such that they subtend an angle of one minute at the observer's eye. An angular scale 24 is fitted to indicate the angle of maximum astigmatism.
GB875722A 1922-03-27 1922-03-27 An instrument for testing visual astigmatism Expired GB197147A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB875722A GB197147A (en) 1922-03-27 1922-03-27 An instrument for testing visual astigmatism

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB875722A GB197147A (en) 1922-03-27 1922-03-27 An instrument for testing visual astigmatism

Publications (1)

Publication Number Publication Date
GB197147A true GB197147A (en) 1923-05-10

Family

ID=9858683

Family Applications (1)

Application Number Title Priority Date Filing Date
GB875722A Expired GB197147A (en) 1922-03-27 1922-03-27 An instrument for testing visual astigmatism

Country Status (1)

Country Link
GB (1) GB197147A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2642771A (en) * 1949-06-13 1953-06-23 Guist Gustav Device for detecting and determining refraction anomalies of the human eyes

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2642771A (en) * 1949-06-13 1953-06-23 Guist Gustav Device for detecting and determining refraction anomalies of the human eyes

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