摘要目的 探讨中文阅读视力表设计的可行性和基本表达.方法 阅读视力表中文字水平确定为小学三年级水平,字体为宋体；句子为包含30个字符的连续文本,每个句子中包含27个常用汉字(即2个标点之间的汉字个数为9个),3个标点符号；所选的80个句子之间无上下文线索,具有独立的意义；字体大小有13种,增率为0.1对数单位,即1.2589,与标准对数视力表的增幅与增率对应；字体大小以2.5点数(pt)为临界阈值.选取29位裸眼或矫正视力≥1.0的受试者,在40 cm检查距离,阅读80个筛选的句子,句子字体大小为2.5 pt(接近正常视力者的视敏度阈值),试验时记录阅读所用的时间和读错的汉字个数.将阅读速度、有效阅读位置和总笔画数3个因素作为精确选取视标的标准,选取39句视标,随机分成3组行配对t检验,以3组之间差异无统计学意义为原则进行多次随机检验.结果 阅读视力表的构成:文化水平为小学三年级,笔画数为165～210,平均(185±10).在阅读视力阈值2.5 pt时,所有测试者都顺利通过；有效阅读速度平均(142.93±11.80)汉字/min；有效阅读位置为36.03～61.48,平均48.85±6.81.39个句子进行分组后测量,差异无统计学意义(P＞0.05)的3组视标的数据:3个组的有效阅读速度分别为(142.49±12.14)、(142.86±12.55)和(143.44±11.63)汉字/min(t1-2=-0.899,t2-3=-1.295,t1-3=-1.435),阅读位置分别为48.55±6.69、48.99±7.49和49.00±6.76(t1-2=-1.019,t2-3=-0.019,t1-3=-0.816),笔画数分别为185.54±7.55、187.69±13.76和182.62±8.17(t1-2 =0.191,t2-3=1.385,t1-3=1.686).结论 中文阅读视力表的设计要素即包含视标大小和增率的视力表设计的基本要素,亦包含视标可读性、连贯和理解的阅读特质.可用阅读视力、临界阈值、有效阅读速度来表达阅读视觉功能.

abstractsObjective Reading is a visual function human being used to understand environmental events based on writing materials.This study investigated the feasibility of reading visual acuity chart in assessment of reading ability by analysis of the key factors involved in the design of the visual acuity chart.Methods The reading level was determined as grade 3 primary school with Song as the font and 30 characters included in the sentences.Each of the sentences consisted of 27 commonly-used Chinese characters (9 characters between any two punctuations) and 3 punctuations.There were no contextual clues between the 80 sentences selected.The characters had 13 different sizes with an increment of 0.1 log unit (e.g.1.2589) and 2.5 pt was determined as the critical threshold.Readable test for visual target was followed as ① 29 candidates with a raw or corrected visual acuity (VA) of at least 1.0 were selected to read 80 selected sentences with the size of characters of 2.5 pt at a distance of 40 cm,②the time used for reading with the number of characters wrongly read was recorded,③39 sentences were selected as visual targets based on reading speed,effective reading position and total number of character strokes,④The 39 selected sentences were then randomly divided into 3 groups with no significant difference among the groups in the 3 factors listed at ③with paired t-test.Results This reading visual chart was at level of Grade 3 primary school with a total stroke number of 165-210(Mean 185 ± 10),13 font sizes a 0.1 log unit increment,a song pattem and 2.5 pt as the critical threshold.All candidates achieved 100％ correct in reading test under 2.5 pt with an effective reading speed as 120.65-162 wpm (Mean 142.93 ± 11.80) and effective reading position as 36.03-61.48 (Mean 48.85 ± 6.81).The reading test for the 3 groups of sentences showed effective reading speed as (142.49 ± 12.14) wpm,(142.86 ± 12.55) wpm and (143.44 ± 11.63) wpm respectively(t1-2 =-0.899,t2-3 =-1.295,t1-3 =-1.435).The reading position was 48.55 ± 6.69,48.99 ± 7.49 and 49.00 ± 6.76,respectively (t1-2 =-1.019,t2-3 =-0.019,t1-3 =-0.816).The total number of character strokes was 185.54 ± 7.55,187.69 ± 13.76 and 182.62 ± 8.17,respectively(t1-2 =0.191,t2-3 =1.385,t1-3 =1.686).Conclusions A practical design of the Chinese reading visual chart should consider size,increment,legibility in selection of reading sentences.Reading visual acuity,critical threshold and effective reading speed could be used to express the reading visual function.