Many studies have reported on visual function in individuals with autism spectrum disorder (ASD) (Simmons, et al., 2009). Vision screening has been compared in ASD and typically developing (TD) peers (Milne, et al., 2009). To date, no study has reported results of vision testing within a comprehensive eye examination protocol in the ASD population nor compared that to a sample of TD peers. This information is needed to diagnose and manage vision problems and to establish a standard of care for ASD patients.
An eye examination protocol was designed to accommodate the communication and sensory challenges associated with ASD. This study compared vision testing in this protocol for ASD patients to that of TD peers.
61 children and adolescents ages 9 to 17 years and who were TD (n=27) or had ASD (n=34) were recruited. A psychologist determined group status/eligibility using DSM-IV-TR criteria after review of previous evaluations and parent report of symptomatology on the Social Communication Questionnaire.
Prior to the eye examination, patients’ parents provided information regarding patients’ gender, race, ethnicity, and communication level (nonverbal, minimally verbal, verbal). Parents indicated whether the patient wore a refractive correction, had ever had an eye examination, and patient's age at the last examination.
The eye examination protocol included tests of visual acuity, refraction, convergence (eye teaming), stereoacuity (depth perception), ocular motility, and ocular health. Tests minimized tactile sensitivity issues and incorporated visual, sensory, and communication supports. All patients were examined according to the protocol. Patients’ refractive findings and habitual spectacle correction were compared to standardized criteria. Patients with significant differences were retested after wearing new spectacle prescription for one month. Chi-square, Wilcoxon Rank Sum test, and ANCOVA were used to compare results for the TD and ASD groups.
TD and ASD groups did not differ by age (p-value 0.54), gender (p-value 0.53), or ethnicity (p-value 0.22). ASD patients were less likely to be corrected for refractive error (44% compared to 15%, p=0.014). Binocular visual acuity after wearing appropriate correction was poorer for ASD patients (p=0.006). ASD patients were more likely to show reduced convergence on near point of convergence (48% compared to 7%, p<0.001) and positive fusional vergence testing (39% compared to 15%, p=0.042). Stereoacuity was poorer in ASD patients (p<0.0001). Ocular motility accuracy was reduced in ASD patients. Testability was generally high (TD 100%; ASD 88-97%), except for intraocular pressure (IOP) measurement. IOP testability was significantly reduced for ASD patients (71 % compared to 89 %) (p= 0.083) and varied with communication level (p< 0.001); 37.5 % for nonverbal, 44.4 % for minimally verbal and 100 % for verbal ASD patients.
Most patients with ASD can complete vision testing within an eye examination protocol. Testability of intraocular pressures is reduced, particularly for nonverbal and minimally verbal patients. Patients with ASD are more likely to have significant uncorrected refractive error, poorer corrected binocular visual acuity, reduced convergence, and less accurate eye movements. Future research is needed to refine examination procedures and investigate treatment implementation in this population.
See more of: Treatment Trials: Behavioral Interventions
See more of: Prevalence, Risk factors & Intervention