GB443495A - Sight testing device - Google Patents
Sight testing deviceInfo
- Publication number
- GB443495A GB443495A GB2491034A GB2491034A GB443495A GB 443495 A GB443495 A GB 443495A GB 2491034 A GB2491034 A GB 2491034A GB 2491034 A GB2491034 A GB 2491034A GB 443495 A GB443495 A GB 443495A
- Authority
- GB
- United Kingdom
- Prior art keywords
- disc
- lines
- curves
- marked
- circumference
- 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
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)
- Cookers (AREA)
- Cereal-Derived Products (AREA)
- Food-Manufacturing Devices (AREA)
Abstract
443,495. Sight - testing apparatus. CULVER, Ltd., G., White Lion Street, Pentonville, London, and MILLS, I. A., 12, Mavis Avenue, Cookridge, near Leeds. Aug. 29, 1934, No. 24910. [Class 97 (i)] A chart for use in testing astigmatism consists of a base 1 on which is rotatably mounted a member 2 provided with a series of lines 6, 7 having appreciable thickness so as to constitute " blacknesses " and arranged end to end with each line inclined at a convenient angle, e.g. 5‹ to the next; so as to form three apparent curves 3, 4, 5 which are convexly curved towards each other and are symmetrically disposed about the axis of rotation of the disc 2. The curves are asymptotic to radial lines 9 marked on the disc and dividing its circumference into three equal parts. To enable adjacent lines 6, 7 to be distinguished from each other, gaps 8 are left between them. Each apparent curve 3, 4, 5 may be extended at each end by longer rectangles 3<1>, 4<1>, 51. The base 1 is marked with an angular scale around the circumference of the disc 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2491034A GB443495A (en) | 1934-08-29 | 1934-08-29 | Sight testing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2491034A GB443495A (en) | 1934-08-29 | 1934-08-29 | Sight testing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB443495A true GB443495A (en) | 1936-03-02 |
Family
ID=10219187
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB2491034A Expired GB443495A (en) | 1934-08-29 | 1934-08-29 | Sight testing device |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB443495A (en) |
-
1934
- 1934-08-29 GB GB2491034A patent/GB443495A/en not_active Expired
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