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Abstract Objective: To study the characteristics of the ocular accommodation and convergence functions in dyslexic
children, and to provide evidence for the prevention and clinical treatment of dyslexia. Methods: In this
case control study, cluster random sampling was used for a questionnaire survey of 2 301 children in
grades 3 to 5 in two primary schools in the Dongli district of Tianjin. One hundred and two children with
dyslexia were the dyslexic group and 102 children without dyslexia matched for age, gender and grade
were the control group. The dyslexic children were identified based on the criteria for dyslexia. Each child
in the two groups underwent complete measurements of visual acuity, refractive error, near stereo vision,
strabismus angle, accommodative amplitude (with moving near measurement), accommodative response
(FCC), relative accommodation, accommodative convergence/accommodation (AC/A) ratio, near point of convergence (NPC), relative convergence and so on. The t test and χ2 test were used to analyze the
differences between the two groups. Results: The refractive errors of the children in the control group and
the dyslexia group were -2.08±2.18 D and -1.95±2.00 D, and the difference between the two groups was
not significant. The dyslexic group's accommodative response was 0.21±0.35 D while the control group's
response was 0.02±0.63 D, and there was a statistically significant difference between two groups (t=5.065,
P=0.011). The dyslexic group's PRA was -1.88±1.06 D while the control group's was -2.77±1.82 D,
and the difference between the two groups was statistically significant (t=-2.153, P=0.040). The dyslexic
group's accommodative facility was 5.43±4.25 cpm while the control group's was 8.20±2.26 cpm, and
there was a statistically significant difference between two groups (t=2.402, P=0.027). The dyslexic group's
AC/A was 3.09±0.84 Δ/D while the control group was 3.81±0.81 Δ/D, and the difference between two
groups was statistically significant (t=2.491, P=0.025). Conclusions: These results show that there are
differences in ocular accommodation and convergence between dyslexic and normal children, and the main
problems are accommodative insufficiency and convergence insufficiency.
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