CRT-based Dark Adaptometry in Adults with Autism.

Many individuals with Autism Spectrum Conditions (ASC) experience sensory symptoms such as dislike of the dark or flashes of bright lights (Baranek et al., 1997; Kern et al., 2001; Bogdashina, 2003). We examined whether such differences in sensory experience could be caused by altered retinal function by measuring dark adaptation in a group of individuals with ASC and a group of age- and IQ-matched controls. A localised 30–98 % visual pigment bleach was performed on participants' natural pupils and then threshold sensitivity to a peripherally presented light stimulus was measured over a period of up to 30 minutes. A single exponential + linear model was fit to participants' data, producing model coefficients that capture cone and rod driven phases of visual sensitivity recovery. Modelling the data in this way produced no significant group differences for any of these measures, even when controlling for percentage photo-pigment bleach and scotopic pupil size. Exploratory analyses were carried out using the Adult Sensory Questionnaire (ASQ) scores and Autism Diagnostic Observation Schedule (ADOS) diagnoses. Model coefficients were not significant predictors of ASQ scores; however, separation of participants into groups on the basis of ADOS diagnosis revealed differences between participants with an ADOS diagnosis of Asperger's and those with a diagnosis of Autism. Further experimental testing with larger sample sizes is needed to fully understand this finding but the present results indicate that low-level adaptive processes in visual processing are largely preserved in adults with autism. Meeting abstract presented at VSS 2016