Runge P E
Department of Ophthalmology, University of South Florida, Tampa, Florida, USA.
Trans Am Ophthalmol Soc. 2000;98:375-438.
Eduard Jaeger's original Test-Types were carefully evaluated: (1) to determine whether Jaeger had maintained a consistent standard, (2) to establish the correct Snellen equivalent for Jaeger's Test-Types, (3) to answer the question of why and how the standard was lost, and (4) to compare the visual angle of optotypes to lines of continuous text.
All original Viennese editions of Jaeger's Test-Types, as well as first generation United Kingdom (UK) and United States (US) versions, were evaluated. Data were collected objectively using a microruler with a 20X loupe and subjectively using a laser distance-measuring device. The data were analyzed using Microsoft Excel. All previous measurements of Jaeger's Test-Types, objective and subjective, collected over the past 133 years were compared to the current data and to each other.
The correct Snellen equivalent of Jaeger's Test-Types was determined. The visual angle created from the measurement of the height of lowercase letters, without ascenders or descenders, provides an accurate method of assigning a visual angle of a line of continuous text. Comparing the typefaces used in printing first generation UK and US versions of Jaeger's Test-Types to the Viennese editions provided an explanation for the absence of a consistent standard for Jaeger's Test-Types today.
All 10 versions of Jaeger's original Test-Types are virtually identical and established a gold standard for reading vision tests. Jaeger's standard was lost when his Test-Types were first printed in the UK and the US using local typefaces. The Jaeger standard has been re-established. Visual angles determined using continuous text are comparable to those obtained by using optotypes.
对爱德华·耶格最初的测试类型进行仔细评估：（1）确定耶格是否保持了一致的标准；（2）确定耶格测试类型的正确斯内伦等效值；（3）回答标准为何以及如何丢失的问题；（4）比较视标与连续文本行的视角。
对耶格测试类型的所有原始维也纳版本以及第一代英国和美国版本进行评估。使用带20倍放大镜的微型尺子客观收集数据，并使用激光测距装置主观收集数据。使用微软Excel对数据进行分析。将过去133年中收集的所有之前对耶格测试类型的客观和主观测量数据与当前数据相互进行比较。
确定了耶格测试类型的正确斯内伦等效值。通过测量不带上下伸部的小写字母高度所产生的视角，为确定连续文本行的视角提供了一种准确方法。将第一代英国和美国版本的耶格测试类型印刷中使用的字体与维也纳版本进行比较，解释了如今耶格测试类型缺乏一致标准的原因。
耶格最初的测试类型的所有10个版本实际上是相同的，并为阅读视力测试确立了黄金标准。当耶格的测试类型首次在英国和美国使用当地字体印刷时，他的标准丢失了。耶格标准已重新确立。使用连续文本确定的视角与使用视标获得的视角相当。
