We have just had a short report published in Molecular Autism: Latham K, Chung STL, Allen PM, Tavassoli T, Baron-Cohen S. Spatial localisation in autism: evidence for differences in early cortical visual processing. Molecular Autism 2013, 4:4 doi:10.1186/2040-2392-4-4.
We know that people with autism spectrum conditions (ASC) perceive the world differently to people without autism, but it isn’t clear where these differences start to arise and whether they are solely perceptual or if there are also differences in basic visual processing. We’ve previously shown (Tavassoli et al., Vision Research 51:1778-1780, 2011) no differences in visual acuity, limited at the retinal level, in autism. In this study we have examined line vernier acuity in autistics and controls, a task thought to be determined in the early stages of cortical visual processing. Whilst there was no difference between the responses of ASC subjects and controls in an abutting vernier task, ASC subjects showed slightly better thresholds than controls on a separated vernier task and a much stronger relationship between abutting and separated thresholds, suggesting that (unlike in controls) the 2 tasks might be mediated by similar mechanisms.
I hasten to add that this preliminary study needs further exploration. But we think that this finding is rather interesting, and suggests the possibility that vision in autism might start to differ at the level of basic cortical visual processing rather than being restricted to higher level perceptual differences.