These visual studies highlight the dilemma of addressing the social difficulties of autistic individuals by behavioral or 'visual learning' strategies alone. When research tracked the eye movements of autistic subjects looking at faces, they found a very different pattern of visual focusing compared to non-autistic controls. This pattern suggests a visual field defect: The lines on the faces indicate where an autistic (left) or control (subject) fixed their gaze as they were looking at the photographs. The control subject focused on the eyes and the triangular area involving the bridge of the nose (an area with a lot of emotional content information), whereas the autistic subject appeared to study only the right side of the face.
In another study, when autistic and control subjects watched a movie, autistic subjects preferred to focus on the lower part of the face instead of in the line of gaze.
These patterns of visual scannings likely have a variety of causes, including visual field neglect, impaired emotional perception pathways(if you don't get much information, why look?), or auditory processing impairment (reading lips). Interestingly, we have seen some autistic children respond well to prism glasses shifts of their visual field- in some children the prisms resulted in improved eye contact, social interaction, and language...so something to keep in mind.
The research studies show that 'lumping' children with autism diagnoses together irrespective of their individual neurological factors is a bad idea. Although some researchers have voiced an interest in evaluating these children more specifically on the basis of language, auditory processing, or visual processing impairments - unfortunately, this research idea has not trickled down to many children yet.
Mapping Visual Scanning In Autism
Visual Perception in Autism