comparison of an italian chart with an iranian chart in visual acuity measurement

background: taking visual acuity is an important part of an eye routine examination. this study was conducted to compare visual acuity measured using an iranian digital tumbling e chart with visual acuity measured using an italian digital tumbling e chart as a familiar foreign chart. materials and methods: this study was carried out on 200 participants (400 eyes; healthy n=40, glaucoma n=40, retinal disorders n=40, post lasik n=40, corneal n=40) with mean age 44.28 years. visual acuity of both eyes of half of the subjects (n=100, n=20 from each group), was first measured using the italian digital chart and then measured using iranian digital chart. visual acuity of the rest of subjects (n=100, n=200 from each group) was first measured using the iranian digital chart and then measured using the italian digital chart. measured visual acuities were recorded in logmar notation. results: the mean of the iranian and italian tumbling e chart is 0.280±0.012 and 0.277±0.012, respectively. paired t-test used to evaluate the mean difference between two groups (p=0.721) indicated that there was no statistically significant difference between means of the two tests. spearman correlation coefficient for the results of both tests was 0.942 (p<0.001), which was statistically significant and could be categorized as a strong positive correlation. conclusion: the two digital tumbling e charts acted similarly at different levels of acuity in different disorders. however, the iranian chart requires a more accurate design for optotypes of the lower acuity lines in order to obtain more accurate measurement of visual acuities in healthy subjects.