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BS 4274(1968) : AMD 9200

Superseded
Superseded

A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.

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superseded

A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.

SPECIFICATION FOR TEST CHARTS FOR DETERMINING DISTANCE VISUAL ACUITY
Superseded date

15-08-1996

Published date

23-11-2012

Specification
1 Scope
2 Definitions
3 Range of letter sizes
4 Indication of letter size
5 Style and selection of letters
6 Spacing of lines
7 Spacing of letters
8 Proportions and line widths of letters
9 Dimensions of Landolt ring characters
10 Dimensions of illiterate E characters
11 Manufacturing tolerances
12 Luminance contrast
13 Lighting requirements
Appendices
A General recommendations on lighting for test charts
B Simple methods of lighting for externally
     illuminated charts
Tables
1 Range of letter sizes and numbers of letters per
     line
2 Minimum and maximum lengths of each line of letters
3 Summary of recommendations on lighting for test
     charts
Figures
1-4 Simple methods of lighting for externally
     illuminated charts. Methods 1-4

Provides basic requirements for test charts designed for either internal or external illumination, employing English capital letters to determine the distance visual acuity. Covers definitions, range of letter sizes, style and selection of letters, spacing of lines, proportions and line widths of letters, dimensions of Landolt ring characters, dimensions of illiterate E characters, manufacturing tolerances, luminance contrast and lighting requirements. BS AMD 9200 RENUMBERS THIS STANDARD

Committee
HCC/78
DevelopmentNote
Superseded and renumbered by BS 4274-1(1968) (10/1996)
DocumentType
Standard
PublisherName
British Standards Institution
Status
Superseded
SupersededBy

BS 3521-1:1991 Terms relating to ophthalmic lenses and spectacle frames Glossary of terms relating to ophthalmic lenses
EN ISO 8429 : 1996 Optics and optical instruments - Ophthalmology - Graduated dial scale (ISO 8429:1986)
BS 3521-2:1991+A1:1996 Terms relating to ophthalmic lenses and spectacle frames Glossary of terms relating to spectacle frames
BS EN ISO 8429:1997 Optics and optical instruments. Ophthalmology. Graduated dial scale
ISO 8429:1986 Optics and optical instruments Ophthalmology Graduated dial scale

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