New Design Principles for Visual Acuity Letter Charts
作者:
Ian Bailey,
Jan Lovie,
期刊:
American Journal of Optometry and Physiological Optics
(OVID Available online 1976)
卷期:
Volume 53,
issue 11
页码: 740-745
ISSN:0093-7002
年代: 1976
出版商: OVID
数据来源: OVID
摘要:
This paper introduces new principles for the design and use of letter charts for the measurement of visual acuity. It is advocated that the test task should be essentially the same at each size level on the chart. Such standardization of the test task requires the use of letters of equal legibility, the same number of letters on each row, and uniform between-letter and between-row spacing. It is also advocated that, combined with the test task standardization, there should be a logarithmic progression of letter size. Charts incorporating these design features have been made. These charts facilitate the use of nonstandard testing distances which might be used when there is low visual acuity, when examination room layout prevents testing at the standard distance, or when it is necessary to validate visual acuity scores or detect malingering. Adjusting the visual acuity score according to the chosen testing distance is simplified by the use of logarithmic scaling
点击下载:
PDF
(357KB)
返 回