Abstract
Purpose: :
The broadening of the diagnosis for autism spectrum disorder (ASD) has made it the fastest rising neurodevelopmental disorder, with an incidence in children now greater than 1%. Given that children with ASD appear to have visual symptomology, it is surprising that no systematic ophthalmic studies have been conducted on this population, and the few limited reports are equivocal. Here we report on the first comprehensive study of basic functional vision in this population.
Methods: :
44 patients (8 female, 36 male; age range: 3-22 years) with a primary diagnosis of ASD were tested with a battery of screening tests developed for our early childhood eye and vision screening program (Adams et al, ARVO 05,07,08,09). These included measures of visual acuity, a full test of ocular alignment, stereoacuity, refractive error, contrast sensitivity (CS), and Vernier acuity. Children were tested monocularly and with optical correction if prescribed.
Results: :
95% of the patients completed all tests in both eyes. The data were separated into 2 age groups, 3-6-year-olds (n=21) and 7+ years (n=23). Compared to controls, 3-to- 6 year-olds showed moderate deficits in visual acuity (M = 20/48; 0.38 LogMAR), CS (M= 53 CS units), Vernier acuity (M =0.70 log min), stereoacuity (M = 2.28 log arcsec) and ocular alignment (31% failed). The older group performed even more poorly, showing significant deficits in visual acuity (20/94; 0.67 LogMAR), Vernier acuity (0.85 log min), stereoacuity (2.41 log arcsec) and ocular alignment (65% failed), but only a moderate deficit in CS (56 CS units). Conversely, across all patients, refractive errors showed a relatively normal age distribution. Using standard pediatric referral criteria, 62% of the younger and 74% of the older group were referred to an eye care specialist.
Conclusions: :
Children with ASD are at risk for eye and visual dysfunction. Given that most children were cooperative, this does not appear to be a compliance issue. On the other hand, given the relatively normal refractive status within this sample, vision deficits appear to have a neural basis.
Keywords: clinical (human) or epidemiologic studies: prevalence/incidence • visual development • visual impairment: neuro-ophthalmological disease