Subramanian Ahalya, Pardhan Shahina
Department of Optometry and Visual Science, City University, London, United Kingdom.
Invest Ophthalmol Vis Sci. 2009 Aug;50(8):3643-7. doi: 10.1167/iovs.08-2823. Epub 2009 Apr 1.
Reading speed and acuity measurements are important means of evaluating reading performance in subjects with impaired vision. The MNREAD charts are gradually becoming a popular means of measuring reading ability in low-vision clinics; yet, to date there are no standards of reliability for the visually impaired population. The present study was conducted to determine the coefficients of repeatability for reading speed, reading acuity, and critical print size in a visually impaired population.
Twenty-seven visually impaired subjects (19 women and 8 men; mean age, 72.07; SD, 12.79 years) participated. Test-retest repeatability of the MNREAD charts was assessed at the subject's preferred viewing distance over two sessions by the same examiner.
The coefficient of repeatability (CR) was found to be +/-0.10 logMAR for reading acuity, +/-0.20 logMAR for critical print size and +/-0.10 logarithm of words per minute for reading speed. The CR was not dependent on visual acuity.
As expected, the coefficients of repeatability are higher in visually impaired subjects than in normal subjects. Critical print size measurements have the poorest reliability and precision and should be interpreted with caution.
阅读速度和视力测量是评估视力受损受试者阅读表现的重要手段。MNREAD视力表正逐渐成为低视力诊所测量阅读能力的常用方法；然而，迄今为止，尚无针对视力受损人群的可靠性标准。本研究旨在确定视力受损人群阅读速度、阅读视力及临界印刷字体大小的重复性系数。
27名视力受损受试者（19名女性和8名男性；平均年龄72.07岁；标准差12.79岁）参与研究。由同一名检查者在受试者偏好的视距下分两次评估MNREAD视力表的重测重复性。
发现阅读视力的重复性系数（CR）为±0.10 logMAR，临界印刷字体大小的CR为±0.20 logMAR，阅读速度的CR为±0.10每分钟单词对数。CR不依赖于视力。
正如预期的那样，视力受损受试者的重复性系数高于正常受试者。临界印刷字体大小测量的可靠性和精度最差，应谨慎解释。
