Objective:To evaluate the consistency between the Kay Picture Test Linear Crowded Book and the standard logarithmic visual acuity chart in preschool children's vision screening and to help the children who could not complete the standard logarithmic visual acuity chart.Methods:A prospective self-controlled study design was performed. One hundred fifty-two preschool children were enrolled from January 2021 to May 2021, who had completed a comprehensive ophthalmological examination and vision test with the KayPictureTestLinearCrowdedBook and the standard logarithmic visual acuity chart. The Wilcoxon sign rank test, Spearman rank correlation analysis and Bland-Altman were used for analysis. Results:One hundred ?fty-two preschool children participated in the screening and 129 children who were without refractive errors and who completed the 2 visual acuity tests were included. There were 74 males and 55 females among the 129 children with a mean age of 52.3±7.0 months. Acuities were 0.1(0.09, 0.1)LogMAR measured by the KayPictureTestLinearCrowdedBook and were 0.1(0.1, 0.22) LogMAR for the standard logarithmic visual acuity chart. There was a good correlation between the two charts (r=0.436,P<0.001). The visual acuity level measured by the Kay Picture Test Linear Crowded Book was higher by 0.04 LogMAR than with the other chart (Z=-6.124,P<0.001). Bland and Altman scatter plots showed that 98.4% of the points were within the 95% limits of agreement. The degree of cooperation for the KayPicture TestLinearCrowdedBook was higher than for the standard logarithmic visual acuity chart (χ2=18.007,P<0.001). The visual acuities measured by the Kay Picture Test Linear Crowded Book were signi?cantly different for different ages groups (H=13.791,P=0.003), with a trend that increased with age.Conclusions:The KayPictureTestLinearCrowdedBook can be used for vision screening in preschool children with a good measurement consistency and higher completion rate compared to the standard logarithmic visual acuity chart. The visual acuity level measured by the KayPictureTestLinearCrowdedBook is higher by 0.04 LogMAR than measurements by the other visual acuity chart, so visual acuity standards should be adjusted appropriately.