Background: Previous studies have shown a correlation between reading problems and binocular function, but few studies have assessed visual skills in dyslexic students, particularly in Iranian Farsi-language students. This study is aimed to determine some of the binocular functions of dyslexic children and compare it with a group of age, sex, and social class-matched control children.
Materials and methods: We conducted a case-control study on 27 dyslexic children and 40 age, sex, and social class-matched control children (all between 7 and 13 years old) in grades one to six. This study was performed at three elementary schools in Tehran, Iran. Monocular and binocular near point of accommodation (NPA) were measured using the subjective push-up method, near point of convergence (NPC) was determined using the standard push-up technique, and stereoacuity was tested with the Titmus stereotypes in all of the children.
Results: Mean NPA of the right eye was 6.90 cm in dyslexic group and 5.98 cm in the control group (P = 0. 003). Mean NPA of the left eye in dyslexic children was 7.32 cm and in the control group was 6.23 cm (P = 0. 003). Mean binocular NPA was 6.66 cm in dyslexic and 6 cm in the control group (P = 0. 049). However, mean NPC (P = 0.33) and mean stereoacuity (P = 0.785) did not differ significantly between the dyslexic and control groups.
Conclusion: Our findings showed a reduced monocular and binocular NPA in dyslexic children so that this function should be assessed by an optometric clinician in children with dyslexia.
Keywords: Accommodation; binocular vision; convergence; dyslexia; stereopsis.