Do you see what I see? It's a simple question. If I look out over the countryside and see the fields, the sun (perhaps not the sun so much here in the UK), how can I be sure that you see exactly what I see? Answer: I can't. For all I know a million people will see a million slightly different versions of the same view; different from what I see as a result of the visual information captured and also what our brain does to those signals.
I recently wrote a post about the suggested changes to DSM V with regards to autism. One of the more welcome proposals to the DSM revisions is the inclusion of a sensory aspect to one of the diagnostic domains, attentive to the growing literature highlighting this particular issue. Although the types of sensory and perceptual issues related to autism detailed by many authors (including those diagnosed with an autism spectrum condition) are wide and numerous, some relate to the visual field.
A few years back, Donna Williams wrote a book called 'Like colour to the blind'. In the book she discusses her various experiences of her autism and in amongst her autobiography, her experiences of her visual perceptual field and her eventual diagnosis of co-morbid scoptic sensitivity syndrome. I remember seeing Donna talk many, many years ago and also remember quite vividly her colour-tinted glasses. Those who have seen Dr Wendy Lawson talk about her experiences of autism might also recognise Wendy's tinted glasses too.
Tinted spectacles (or Irlen lenses as they are often called) are no new thing. Evidence has been emerging for some years that conditions manifesting reading difficulties such as dyslexia may benefit in certain tasks from such an optical intervention. The evidence base is quite large.
When looking at the experimental data relating to the use of tinted lenses specifically in relation to autism, the evidence base gets progressively smaller. I found only a handful of references; the most cited one being this article examining the use of coloured overlays in autism, again with regards to reading comprehension.
The reason why this is relevant relates to the reasons why such lenses are primarily being used. For reading disorders, the general consensus seems to be that tinted lenses can be quite a good way of improving word and reading comprehension for some people. Some authors have attempted to describe the mechanisms as to why they might work (frequency of colour, perceptual filtration, etc) but ultimately we don't really know the full story.
In the case of autism, many people using such lenses however describe other reasons for wearing them. Again, Donna Williams on her website describes them as being useful to: ".. increase the ability to keep up with a greater range of visual information" and "help to better keep up with receptive language". The suggestion from Donna and other accounts from people with autism is that tinted lenses work on other (albeit potentially related) areas; more fundamental to the live streaming physical world outside of just the printed word, and also perhaps multi-modal - visual perception influencing speech perception for example.
I know that there are other aspects to vision perception and autism which are covered in this area such as the use of ambient prism lenses and let us not forget classical problems with the eyes that anyone of us can experience (autistic or not). There is a however a big void in research into this important area for autism. Given the growing recognition of sensory and perceptual issues in relation to autism, one would expect that there are good grounds for some revealing insights to be had from further investigation.