Theme ‘light and sight’
‘Light and sight’ is a theme under the chapter ‘garden/outside area’, ‘architectural spaces’ and ‘interior design’. (See The recommendations.) After sound ‘light and sight’ is the single most prominent subject on this site. (Artificial lighting is a separate theme.)
Light, and daylight in particular, was already viewed by the ancient Greeks as salutory. Research has since established that daylight in hospitals shortens the stay of depressive patients and reduces pain and stress among operation patients. Daylight in the workplace and in schools is conductive to higher achievement. The great relevance of light in the context of autism is precisely because its beneficial effects are hampered by sensory abnormalities of most or all people on the spectrum.
Seeing light and visual perception are (almost) the same thing. Disturbances in it are an important part of the sensory abnormalities from which people with autism suffer generally. Forty percent of people with autism and related disorders suffer from ophthalmological pathology. This can almost entirely be attributed to deviating sensory processing in the brain. (See Coulter.) For instance children with autism have more refractive errors, which may lead to myopia and hyperopia, estimated at 44%, in a small scale study. Strabismus is more prevalent among them as well. Several studies find this at a rate of 20% of Asd-children and one even finds 50%. In daily life a lessened visual sensitivity for certain contrasts is important too.
Both over- and under-sensitivity for visual stimuli can occur – sometimes both in the same person. Hypersensitivity can be turned into an advantage and can even lead to a sharpness of vision which considerably exceeds that of ‘neurotypicals’, sometimes called ‘eagle-eye view’.
Oversensitivity to light is a well known and often observed autism-symptom. From all this it may be clear – to put it mildly – that light is a very sensitive issue.
Architect Humphreys – one of the authors of what we have termed ‘the core-literature’ – finds daylight in buildings essential: “Natural light in any building, how it enters the building will uplift the spirit. Introducing light into a building needs very careful thinking with autism in mind. Too much variety may startle, too much shadow may create repetition as visual stimulation.” He quotes the famous French architect Le Corbusier: “The key is light, and light illuminates shapes, and shapes have emotional power.” (1957)
‘Very careful thinking’ is especially required around three related recommendations under this theme in the chapter ‘architectural spaces’. One (number 77) is about avoiding direct sunlight and strong reflections of it. Subsequently the next one (79) is about allowing sufficient daylight, while the third (80, both in the home, and the school context) deals with moderating this same daylight.
Together these recommendations are aimed at the right balance: generous daylight, but not direct sunlight on the one hand, and on the other generous but not overabundant daylight in order to prevent avoidance of it.
Ample research documents that academic performance in regular schools improves markedly under the influence of sufficient daylight. American research found that students who are exposed to the most daylight in their classrooms advanced 20% more rapidly in math and 26% in reading than those exposed to the least daylight. In Swedish elementary schools it appeared that insufficient daylight “may upset the basic hormone pattern, and this in turn may influence the children’s ability to concentrate or cooperate, and also eventually have an impact on annual body growth and absenteeism.” In Canada elementary school children in classes with full spectrum light were compared with children in conventionally lit school classes. The former group appeared to have fewer days of absence and to be more healthy.
In general then ample daylight is beneficial to schoolchildren and the lack of it correspondingly unfavorable. We are not aware of such research specifically aimed at autistic children. On the one hand mechanisms are at play which work equally for everyone, on the other many autistic children are oversensitive to daylight. This is the reason for the above mentioned balanced recommendations. Specifically an oversupply of daylight may provoke avoidance which renders it counterproductive.
Windows are, of course, essential in this context. There are few, if any, other subjects in building and design in which so many autistic characteristics are implicated as ‘windows’: imperfect Central Coherence, cognitive shifting and low sensory tolerance to both light and temperature.
Large surfaces of glass should be avoided because of the potential problems caused by the overabundance of light, solar gain, reflections, and glare. The potential sensitivity many people have to feeling exposed to prying eyes is another good reason to choose windows that make light and vision management easy. Moreover, the view can be distracting, especially to people on the spectrum who are often prone to over-stimulation and/or uncontrollable fascinations for instance with traffic, trees, pets or birds. (See recommendation 10.)
Henry gives several sources suggesting that a view on concrete and rooftops can be stressful and on nature beneficial.
One of the residents of the Dr. Leo Kannerhuis who were interviewed about this subject summarized this issue quite well: ‘For many people with autism it’s quite unpleasant to be exposed to a low or glaring sun when inside. That’s why it would be smart if windows were placed strategically in a building, with possible blinds. Large windows on the south side are therefore rather awkward, if lessons or meetings take place there. A buildings mainly constructed out of glass should be discouraged. Moreover the surroundings can pull one’s attention to what happens outside…’
The author of this website finds it plausible that sleep problems are in part caused by avoidance of daylight. Generally, people on the spectrum often have sleep problems, (See Richdale and also Limoges et al.), especially children of whom two thirds have them. The causes are unclear. We propose the hypothesis that sleep problems are in part caused by avoidance of daylight as a result of oversensitivity to it.
Daylight is important for the control of our biological (circadian) clock and consequently for our ‘sleep wake rhythm’. Put simply, light, after entering the eye, is transformed into brain impulses which travel to the pineal gland where the release of melatonin (the ‘sleep hormone’) is inhibited. Conversely, when the light diminishes, the release of melatonin is stimulated, which stimulates sleep. (See ‘melatonin’ in Wikipedia.) Recommendation 80 (e.g. in school) of reducing an abundance of daylight in order to prevent avoidance of it, may in part help to reduce sleep problems.
Apart from the merits of this hypothesis, melatonin is the basis of a relatively successful medicine against sleep problems in autistic children. (See this review article.)
Last but not least the excellent (and beautifully illustrated) article by Christopher Henry is warmly recommended. It can be found here.