Assessment of visual function in autistic children.

Children with autism demonstrate "atypical" gaze or social "looking" and frequently manifest such sterotypies as eye pressing, hand flicking, and light gazing. This study's purpose was to evaluate autistic children for visual dysfunction that may be related to the manifested visual signs and symptoms. Thirty-four autistic children, ages 2 to 11 years (median age = 7 years, 6 months) were evaluated for ocular alignment, refractive error, visual acuity, oculomotility skills, and stereopsis. None of the children manifested ocular disease, known seizure disorders, or dysmorphic features. Their developmental levels ranged from average intelligence to severely retarded. Binocular visual acuity was measured with the acuity card procedure. Monocular visual acuity was not obtained. Refractive errors ranged from -4.25 to +3.25 D; the median was plano with the near retinoscopy technique. Of the 34 children, 21% were strabismic at far and 18% were strabismic at near. Lang stereo testing was attempted on all children and completed on 17. Of the 17, all but 3 exhibited 550 sec arc. Only 14.7% of the children exhibited voluntary pursuit movements, and all the children demonstrated saccadic fixations. Thirty-one children had atypical optokinetic nystagmus (OKN) responses such as delayed onset, short duration, gaze avoidance, or stereotypic behavior. Repeated testing revealed consistent visual responses on OKN and visual acuity. Given these findings, research with this population should be pursued further.