Abstract
Purpose :
Binocular vision deficits, although not implicated as a causative factor, have been previously reported in children with dyslexia. However, few studies have evaluated the ocular accommodative profile and symptoms associated with near work in dyslexic children. The purpose of our study was to assess the nature of accommodative deficits in children diagnosed with dyslexia.
Methods :
A prospective observational study was carried out on 30 dyslexic individuals (mean age: 10.29±1.17 years) and 33 typically reading children (mean age: 9.44±1.38 years). All children had a complete cycloplegic eye exam with a detailed binocular vision assessment. The tests for accommodation included: Amplitude of accommodation (AA) using push up method with a 0.8M target. Monocular (MAF) and binocular accommodative facility with a ± 2.00 D flippers, and Accommodative response (AR) to a +2.50 D demand in both eyes. Steady-state accommodative response was objectively measured at 2, 2.5, 3, 4 and 5 diopter demands. Near work related symptoms were assessed using the convergence insufficiency symptom survey (CISS).
Results :
Children with dyslexia had significantly lower AA (Mean ± SD of 10.21± 2.04; 11.5±1.48, p=0.01), lower MAF (5.05± 2.92; 7.31 ±2.37, p = 0.01) and greater lag of accommodation (0.95±0.43; 0.73± 0.30, p= 0.05) compared to controls. Slopes obtained from a linear fit to the objective accommodation responses were not significantly different between the two groups. On CISS, the dyslexic group reported significantly more symptoms than controls (16.0 ±7.34; 3.23±2.53; p=0.01). However, only a weak (although statistically significant) correlation was found between measures of accommodation (AA: r = -0.31; p =0.05; MAF: r =-0.28; p =0.05) and the CISS scores. Deficits in accommodation in the dyslexic group was observed for AA 30%; MAF 27% & AR 20% with a criterion for failure at mean ± 2SD from controls and/or age expected norms.
Conclusions :
Accommodation deficits are seen in about 1/3rd of patients with dyslexia, mostly characterized by reduced AA and/or deficits in MAF. For that reason, at least a sub-population of dyslexic subjects might benefit from a thorough optometric evaluation and treatment. Influence of oculomotor vergence and tracking deficits on CISS needs to be analyzed along with accommodation to understand, if any, the contribution of binocular vision deficits to the near work related symptoms in dyslexia.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.