Optometrists have a duty to provide exceptional comprehensive eye care to all individuals, including those with Autism Spectrum Disorder (ASD), who frequently have significant visual dysfunctions and visual processing deficits. The prevalence of ASD in the United States has doubled since 2007,1 creating an increased demand for eyecare professionals to address visual challenges in these patients.
Barriers to providing adequate vision care to ASD patients may include poor knowledge and understanding of the condition, common behaviors of the patient, and lack of preparation in evaluating and treating these patients.2
The purpose of this article is to provide awareness and knowledge of ASD and the common visual challenges related to the condition. Optometrists should be better prepared to modify visual assessments and meet the needs of future ASD patients.
ASD is the name for a group of developmental disabilities and/or neurological conditions that are characterized by three main criteria; impairments in verbal and non-verbal communication, difficulties with social interaction, and a range of repetitive stereotyped behavior patterns.3
- Difficulties with communication: delayed spoken language, unable to carry conversation, limited abilities in imaginative play
- Difficulties with social interaction: little facial expression, inability to develop peer relationships, lack of social/emotional reciprocity, decreased eye contact
- Repetitive, stereotyped behavior patterns: inflexibility to changes in routine, repetitive motor movements such as lining up objects or hand-flicking, excessive interest limited to single toy, maintains interest in spinning objects for periods greater than a few minutes
These impairments and behaviors can negatively impact learning, attention, and sensory processing. Some of the conditions under the ASD term include autistic disorder, Rett syndrome, Asperger's syndrome, and pervasive developmental disorder. There is no definitive process for diagnosing ASD, however the diagnosis heavily relies on typical behaviors listed in The Diagnostic and Statistical Manual Fifth Edition (DSM-5), the Autism Diagnostic Observation Schedule (ADOS), or the Autism Diagnostic Interview-Revised (ADI-R).3-5 The DSM-5 is commonly used and considers a patient to have ASD if they meet all criteria under the social communication and social interaction domain, in addition to two of four defined symptoms related to restrictive and repetitive behaviors.6
Common Visual Manifestations of ASD
Optometrists play an important role in caring for individuals with ASD. We have the ability to identify signs of ASD based on visual behaviors during the examination.
Common visual signs1,3 include the following:
- Gaze aversion or poor eye contact
- Squints or closes an eye
- Looks at objects sideways or with quick glances
- Intense light sensitivity
- Preference to look at objects (even hyper-fixating on objects) rather than people
- Attracted to shiny surfaces
- Always prefers or avoids a particular color
- Anxiety or avoidance to fast moving objects
In addition, optometrists can assess ASD patients for the following common visual challenges1,3,5,7,8 and take appropriate action to manage these conditions, or refer to other eyecare professionals with more experience in developmental vision and vision therapy.
High Refractive Error and Amblyopia
Oftentimes children with developmental disabilities, including ASD, have high refractive errors. Retinoscopy skills are crucial for identifying uncorrected refractive errors that could put the patient at risk for refractive amblyopia. Cycloplegic retinoscopy can aid in confirming suspicions for high refractive errors, and having the patient wear the potential prescription with a trial frame in-office would be best before prescribing.
Risk factors for unilateral amblyopia if uncorrected:
Hyperopia greater than 1.00 D between each eye
Myopia greater than 3.00 D between each eye
Astigmatism greater than 1.50 D between each eye
Risk factors for bilateral amblyopia if uncorrected:
Hyperopia greater than 5.00 D in each eye
Myopia greater than 8.00 D in each eye
Astigmatism greater than 2.50 D in each eye
Strabismus and poor binocularity
Various studies have shown that strabismus is present in anywhere from 20-50%3,5,8 of ASD patients. Convergence insufficiency is also commonly present in this population. Ocular posture can be measured through the unilateral cover test or Hirschberg reflexes, while the magnitude of an eye turn can be measured through the alternating cover test, a Maddox rod, or Modified Thorington card.
The presence of strabismus often indicates the patient having poor binocularity, therefore consider thorough testing of stereopsis, Worth-4-Dot fusion, near point of convergence (NPC), vergence ranges, and accommodation. These test results will provide a better understanding of the patient’s binocular system and help guide your management plan.
Keep in mind that children with developmental disabilities generally perform better with out-of-phoropter testing. This provides better observations and reliable results for the optometrist.
Fixation, saccades, pursuits, and eye tracking skills can be observed and assessed throughout the examination. Observations of visual behaviors alone can suggest ocular motility issues if there is a constant loss of fixation and gaze aversion during tasks. Optometrists can use the NSUCO Oculomotor Test9 to identify deficits with saccades and pursuits as studies show that saccadic control is often impaired more than smooth pursuit performance.3,8 Additional tests to evaluate eye coordination and tracking skills include the Developmental Eye Movement (DEM) test and the Right Eye device.
Poor spatial planning and awareness
Visuo-spatial processing and spatial planning skills are responsible for body awareness, localizing one’s body in space in relation to other objects, and localizing other objects to other people. An ASD patient with a visuo-spatial processing deficit may rely more on tactile feedback or kinesthetic awareness to find objects in space; relying on proprioception rather than vision.
Therefore, observations during the examination may indicate the patient has difficulty with spatial awareness. Spatial planning skills are also used to organize written material, understand laterality and directionality, and are a key component of eye tracking skills during reading.
Visual perceptual tests such as the DEM, Right Eye device, Gardner Reversal Frequency, Jordan Left/ Right Reversal, Piaget Left Right Awareness, or Test of Visual Analysis Skills (TVAS) are all used to assess spatial planning skills and provides insight into one’s reading ability as well.
Poor sensory integration and reduced processing of peripheral stimuli, faces, and motion
Patients with ASD often have difficulty integrating visual, auditory, and tactile stimuli. Observations of visual behaviors during the examination can provide information to the optometrist of any challenges with sensory integration or processing skills. The patient may look away from the one who is speaking, which suggests the patient is relying on auditory skills rather than integrating visual and auditory skills together.
ASD patients tend to focus on central stimuli (e.g., local processing, details of an object) rather than peripheral stimuli (e.g., global processing, the object as a whole). Therefore, observations by the optometrist may include the patient successfully identifying objects in a visual search task without understanding the context of the entire scene, or recognizing details on faces of characters but having difficulty interpreting emotions from their facial expressions. Challenges with motor processing can influence the patient to avoid looking at fast moving objects.
Modifications and testing considerations for ASD
Making modifications to your examination routine is imperative to provide comfort for the ASD patient and to obtain accurate test results.
|The patient may have difficulty transitioning between activities and strongly react to change.||Try implementing a testing schedule or social story with each test, and offer choices for which test to complete next.|
|The patient may have difficulty understanding verbal instructions.||Try using visual stimuli such as pictures or a live demonstration of the test on another family member.|
|Poor reciprocal communication can be a barrier to tests that require any response from the patient.||Use positive reinforcement such as tokens or stickers to encourage specific responses.|
|The patient can have extreme photosensitivity.||Modify the lighting environment in the examination room.|
|The patient can have hypersensitivity to visual or auditory stimuli.||Ensure the examination room is quiet and free from clutter to avoid sensory overload.|
If ASD is suspected based on visual behaviors during the eye examination, consider adding screening tools in the office to help initiate the conversation and guide additional referrals to other healthcare professionals for further investigation. The Modified Checklist for Autism in Toddlers (M-CHAT) is a tool that optometrists can use in-office and is easily administered to the parent or guardian. The M-CHAT is designed for children between 16-30 months of age at risk for Autism and is often used by healthcare providers to screen for developmental delay and autism.4 It asks 23 "yes/no" questions based on observed behaviors of the child at home.
The M-CHAT can be found on www.mchatscreen.com or www.m-chat.org. In addition, the American Academy of Pediatrics provides a variety of screening tools for healthcare providers and educators to help identify any children at risk of ASD.
Treatments to improve quality of life
Optometrists have the ability to enhance one’s functional vision and quality of life with the use of lenses, prisms, filters, and/or vision therapy. The first step in treatment is aimed towards correcting any refractive error to provide clear, comfortable vision. Consider a bifocal lens or separate reading glasses if the additional plus at near benefits the patient’s ocular posture or accommodative system.
A small amount of opposite or yoked prism could potentially benefit the patient’s ocular posture or spatial awareness, respectively, however, be sure to trial this in-office before prescribing. Colored lenses and/or syntonic phototherapy can be used to address the patient’s sensitivity to light and particular colors.
In addition to these therapies, an individualized vision therapy program should be strongly considered to improve binocularity, ocular motility, and visual processing challenges (e.g., spatial awareness, visual information processing, visual coordination, visual-motor-integration). Numerous publications by optometrists have shown successful results in improving visual functions and processing skills through vision therapy for the autistic patient.
Likewise, accommodations are needed to help the patient maximize their learning ability. Accommodations will allow the patient to work around any visual barriers as they learn coping mechanisms.
Consider the following recommended accommodations for school and home learning environments:
- Learning should be made as multisensory as possible. Encourage the patient to taste, smell, hear, and manipulate objects related to the lessons being taught to help better understand and retain information.
- Recommend a small-group academic setting to reduce visual and auditory distractions.
- Provide a combination of visual handouts with auditory supplements (e.g., videos, music, in-person discussions).
- Use a line guide or window reader to isolate each line when reading.
- Reduce visual clutter by increasing the margin width, use double spacing, and enlarge font size on handouts.
- Use graph paper to organize written information.
- Allow double the amount of time when completing reading tasks.
- Recommend typing assignments as a strategy to circumvent difficulties with reversals and fine motor challenges.
- Provide index cards with letter and number templates to use as a reference if unsure of the orientation of a particular letter or number.
Aside from optometry, patients with ASD need an inter-professional team of speech, physical, cognitive, and behavioral therapists to address all areas of developmental delays that could be present. Be sure to make appropriate referrals as needed and continue open communication between multiple providers and the family members throughout your management plan.
- Fisher J, Phan T. Incorporating behaviour modifications, strategies, and supports to maximize the effectiveness of vision therapy in the autism spectrum disorder population. Vision Dev & Rehab 2019;5(4):255-267.
- Coulter RA. Serving the needs of the patient with autism. Optom Vis Dev 2009;40(3):136-140.
- Coulter RA. Understanding the visual symptoms of individuals with autism spectrum disorder (ASD). Optom Vis Dev 2009;40(3):164-175.
- Jensen KA, Hoppe E, Remick-Waltman K, et al. Update on autism spectrum disorders for optometry: a review of the literature. Optom Vis Perf 2014;2(5):220-234.
- Bhandari G, Neupane S, Shrestha GS. Ocular morbidity in children with autism. Optom Vis Perf 2013;1(1):19-24.
- Hyman SL, Levy SE, Myers SM, et al. Identification, evaluation, and management of children with autism spectrum disorder. Pediatrics 2020;145(1):e20193447.
- Au M, Coulter R. Vision therapy for the autistic patient: a literature review and case report. Optom Vis Perf 2014;2(5):244-250.
- Little JA. Vision in children with autism spectrum disorder: a critical review. Clin Exp Optom 2018;101(4):504-513.
- Maples WC. The NSUCO Oculomotor Test. Santa Ana, CA, Optometric Extension Program Foundation, 1995.