SIGNIFICANCE:There are limited studies assessing reading performance and children's difficulties with dyslexia especially when reading Arabic, a language that has a substantially different script from English and other Latin-based languages.PURPOSE: This study aimed to (1) measure reading performance in children with dyslexia by acuity level and (2) conduct an indirect comparison between the effects of dyslexia on Arabic versus English readers.METHODS: Twenty children aged 9 to 12 years with dyslexia and 30 controls aged 9 to 11 years were included in the study. Reading performance was evaluated using maximum reading speed, reading acuity, and critical print size (CPS). Two Arabic charts, the Balsam Alabdulkader-Leat chart and the International Reading Speed Texts chart, were used to evaluate reading performance. The number of errors was calculated and plotted against print size.RESULTS: ANOVA revealed a significant difference between the two groups in all reading performance measures (P < .05). Reading speed for children with dyslexia was significantly lower than that for the control group (33 vs. 90 standard-length words per minute). Critical print sizes were 0.25 and 0.10 logMAR for children with dyslexia and the control group, respectively. Reading acuity was worse for children with dyslexia in comparison with the control group. Error number above the CPS was significantly higher in children with dyslexia than in the control group.CONCLUSIONS: Reading speed measures were lower for children with dyslexia compared with controls. Children with dyslexia required larger CPS to read at their maximum speed, indicating that larger print sizes may improve reading with greater speed. The difference in reading performance measures between controls and children with dyslexia is higher when reading Arabic than when reading English. This suggests that the intricate Arabic script and crowding may more strongly affect children with dyslexia reading Arabic.