Visual Sensitivity and Autism

The technical term for an abnormal sensitivity to light is photophobia. People with photophobia are bothered by light regardless of whether its source is  natural or artificial. They avert looking directly at lights and, when forced to do so, often squint or close their eyes.  Sustained exposure to visual stimuli may produce headaches prompting the person suffering from photophobia to retreat into a dark room.  As light is omnipresent in our surroundings, this is a debilitating condition that diminishes quality of life and greatly limits work-related options.

Many individuals on the autism spectrum suffer from difficulties in processing and integrating sensory information and, as a result, often under- or over-respond when stimulated. Visual sensitivity or photophobia is one of these sensory processing abnormalities.  This handicap has a profound effect in the way the person reacts to his/her immediate environment. It may force him/her to look one way while talking or pointing in a different direction.  In some extreme instances, photophobia forces the affected individual to constantly touch objects as a tactile mean to better navigate their environment. In addition, it makes recognizing faces more difficult. It is easy to understand how the latter symptom may cascade into difficulties in non-verbal communication and understanding other people’s mental states and emotions.

Fluorescent lights are particularly noxious to autistic individuals.  When a fluorescent tube is connected to main’s line voltage, the corresponding 50 or 60 HZ cycle of alternating current (AC) causes the cyclical discharge of the ionized gas contained in the tube. This is due to the fact that the ionized gas can’t conduct electricity until the voltage is close to its maximum level. This provides a flicker effect which some autistic individuals find disturbing.

I remember attending several AutismOne congresses where autistic individuals who were overstimulated would be directed to the “violet room”. Fluorescent lights in that particular room were covered with a colored gel that made everything reflect a violet color. Not only did the autistic individuals find this comforting but so did everyone else attending. (Note: For those interested in trying out this the product, it is commercially available under various names such as fluorescent light filters, color filters, lighting gel filters, or color sleeves).

Photophobia often results in headaches and many of its symptoms are similar to those experienced by autistic individuals. Many years ago, I wrote an article that attempted to explain the presence of migraine and gastrointestinal symptoms in autism as a serotonergic abnormality (Casanova, 2008- the article is freely available on the internet ). In that article, I explained that:

“Sensory processing abnormalities are correlated with higher levels of repetitive and stereotypical behaviors. From a behaviorist standpoint, some autistic symptoms represent an avoidance reaction to overstimulation. This reasoning has important implications for treatment. Indeed, occasional autistic tantrums are best handled by diminishing all sources of stimulation; e.g., going into a room and closing all windows, turning off the light, etc. Visual overload is a common phenomenon in autism, especially troublesome is the flickering of fluorescent lights. Transitional prism lenses modify distortions of ambient vision. Their use has also been shown to diminish behavioral problems in a double-blind crossover study of autistic patients. Many of these patients are photosensitive and experience some benefit from wearing photoreactive lenses.”

I have often wondered whether treatment of photophobia and gastrointestinal upset in autism could benefit from antimigraine medication. In this regard I wrote an opinion in the same article previously cited (Casanova, 2008):

“Some of the behavioral symptoms of autism, specifically the repetitive behaviors, are strongly related to serotonergic (5HT) dysfunction. It has also been reported that Sumitriptan, a 5-HT1d receptor agonist and an antimigraine medication, improved symptoms of autism and migraine in patients who suffered from both disorders. Although Sumitriptan is primarily a 5-HT1d receptor agonist it may also bind to other subtypes of 5HT receptors. Double blind studies of serotonin reuptake inhibitors, clomipramine, and fluvoxamines as well as open label studies of fluoxetine and sertraline, have documented efficacy in treating various symptoms of autism. Depletion of 5HT precursor tryptophan, have been shown to induce a worsening of autistic symptoms in some but not all patients.” Much more research is needed on this subject.

Other potential treatment options include avoidance of potential triggers and wearing glasses with filtered lenses. Among precision tinted glasses those that block the blue light spectrum are preferred. There are some studies reporting that blue lights promote migraines and disrupt the wake-sleep cycle. Sunglasses are not recommended as they will dark-adapt the retina and ultimately aggravate the sensitivity to light.  Avoid use of fluorescent lights but, if forced to use them, cover the bulbs with gel filters.

References

Casanova MF. The Minicolumnopathy of Autism: a Link between Migraine and Gastrointestinal Symptoms. Med Hypothesis 70(1):73-80, 2008.

5 responses to “Visual Sensitivity and Autism

    • Yuvall, do you think Simon, a “neurotypical ally” of neurodiversity is doing it because he believes in it, or he knows he can make a buck off it? Both?
      What impression do you get from him?

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  1. Hi Manuel, I am curious to know why you suggest only tinted lenses in the green to blue light spectrum. Have you read any of the studies conducted by Wilkins and Ludlow? Wilkins has investigated the use of tinted lenses in Migraine, Epilepsy and filters for children who have Autism. I’d like to investigate this area further myself. I have some serious ground work to do before I am ready to embark on this.
    An interesting article yet again. Thank you for sharing your thoughts.

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    • I said green and blue lights from memory as to what I remember having read. Green and blue fall towards one end of the light spectrum that provide for shorter wavelengths and higher frequencies. I work with LEDs in electronics and use the color code when reading resistors values. It is easy for me to lump them together. In the blog, I made reference to an analogy to migraines. I shouldn’t have trusted my memory. Blue light tends to propitiate migraine. The flicker that you see in many fluorescent bulbs, TV sets and even cell phones falls on this wavelength spectrum. Blue light is quite prominent during the day (if you shine a blue LED on a yellow phosphor you get white, the color of daylight). Some people claim that you should avoid it at night as it may disturb your sleep pattern. So avoiding blue colors and using a filter makes sense to me. I should have stopped there and not included green. Autistic kids have a preference for green colors and some studies claim that it may reduce migraine headaches. I will try to correct the blog later. Thanks for your comments.

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