Autism and Vision

Autism and Sight

There has been several recently published articles on autism with some dysfunctions being found at a higher rate than in the neuro-typical population. One study, published in January 2017, found consistently that children with autism reacted slower to changes in light (pupillary light reflex). The pupillary light reflex was slower when lighting changed and, in darkness, the pupil measured smaller than controls.(1)

A second study, published in 2018, found a higher rate of accommodative problems (17.4% for ASD, vs 4.9% control) for children diagnosed with autism. While there was no substantial difference in the rate of refractive error, this higher rate of accommodative problems makes a complete eye exam with assessment of near vision acuity more important.(2)

A review of evidence found several contradictory studies concerning the prevalence of eye movement defects associated with autism, though most agree that saccades inaccuracy as well as difficulties in tracking are common in ASD. These movement problems, coupled with other fine and gross motor deficits found in autism suggests a cerebellar problem.(3)

Autism and Vision

Difficulties with the integration of visual information is found in several studies. All of these studies point to a lack of integration between the parvocellular and magnocellular tract and reduced communication between these tracts.(3)

Studies found differences in VEPs (visually evoked potentials) studies in the activity of the magnocellular tract compared to neuro typical children. The difference was, most notably, a slower recovery period for the magnocellular tract and therefore, decreased integration of the information. Functionally, this may help explain the visual spatial problems frequently seen in ASD diagnosed children. (4, 5)

Lateral gazing’ behavior was also found in some children with ASD as they attempted to use peripheral vision to reduced central visual pathway input. (3) This behavior is also suggestive of magnocellular tract deficits.

Integration Deficits

A common thread through many of these studies is a decreased integration of visual information and motor pathways and the cerebellum. (6) This lack of integration could help explain the ocular motor and saccade problems, as well as increased incidence of gait problems and toe walking (7,8) and visual motor integration problems found in children with ASD. A study also showed that people with ASD do not make good use of visual information to correct posture (9). Addressing this lack of integration could be helpful making functional progress with children on the spectrum.

Summary

A complete binocular vision exam with cycloplegic dilation is very important for every child with autism (and neuro typical children too) given the potential for a higher rate of accommodative and ocular motor problems and fine motor, reading and handwriting problems.

Given the evidence of integration problems, activities for children with ASD should be “top down” type activities that require the integration of movement and vision.

Much of this research is very recent and found some changes from previous research. Many of the studies suggested these differences in results were related to redefining autism with the release of DSM-5 eliminating Aspergers and pervasive developmental disorder and grouping these into the current terminology of autism spectrum disorder. The inclusion of these subjects in studies have helped improve the understanding of vision and autism. Many of the studies also sited small samples as potential limitations.

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(1)Anketell, P. M., Saunders, K. J., Gallagher, S. M., Bailey, C., & Little, J. A. (2018, March). Accommodative Function in Individuals with Autism Spectrum Disorder. Retrieved March 05, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/29424829

(2)DiCriscio, A. S., & Troiani, V. (2017, July 25). Pupil adaptation corresponds to quantitative measures of autism traits in children. Retrieved March 05, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/28743966

(3)Bakroon, A., & Lakshminarayanan, V. (2016, July). Visual function in autism spectrum disorders: a critical review. Retrieved March 05, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/27161596

(4)Jackson, B. L., Blackwood, E. M., Blum, J., Carruthers, S. P., Nemorin, S., Pryor, B. A., . . . Crewther, D. P. (2013, June 18). Magno- and Parvocellular Contrast Responses in Varying Degrees of Autistic Trait. Retrieved March 05, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/23824955

(5)Sutherland, A., & Crewther, D. P. (2010, July). Magnocellular visual evoked potential delay with high autism spectrum quotient yields a neural mechanism for altered perception. Retrieved March 05, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/20513659

(6)Miller, M., Chukoskie, L., Zinni, M., Townsend, J., & Trauner, D. (2014, August 01). Dyspraxia, motor function and visual-motor integration in autism. Retrieved March 05, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/24742861

(7)Accardo, P. J., & Barrow, W. (2015, April). Toe walking in autism: further observations. Retrieved March 05, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/24563477

(8)Kindregan, D., Gallagher, L., & Gormley, J. (n.d.). Gait deviations in children with autism spectrum disorders: a review. Retrieved March 05, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/25922766

(9)Morris, S. L., Foster, C. J., Parsons, R., Falkmer, M., Falkmer, T., & Rosalie, S. M. (2015, October 29). Differences in the use of vision and proprioception for postural control in autism spectrum disorder. Retrieved March 05, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/26314635

Fine motor skills and vision

Does binocular vision affect fine motor ability?

Occupational therapy has been treating fine motor problems since the beginning of the profession. From tying shoes to buttoning to handwriting, when children or adults have difficulty with this, occupational therapy is referred.

Binocular vision?

A small study (1) looked at the fine motor skills of children with reading difficulties and found those with fine motor problems also had binocular vision problems, specifically accommodative problems.  While a small study (19 children), this suggests that vision is playing a role in fine motor coordination.

Another study (2) found that children that were poor readers showed a higher occurrence of binocular vision difficulties and suggested a need for the assessment of these skills in problem readers.

Research also indicates the importance binocular vision and motion perception to development of the motor skills(3) as young a 2 years old.

OT and binocular vision

As therapists, we are seeing children with difficulties that could have a binocular vision component. While a through binocular eye exam should be completed to rule out treatable defects, therapists integrating tracking, saccade and convergence activities could help improve outcomes for their patients. Our background in developmental sequence, kinesiology and assessment of functional ability make therapists the perfect profession to address these deficits. As therapists, we address the motor part of visual motor problems, but basic tracking, eye-hand coordination tasks could help with outcomes by improving the visual aspects of this skill.

The Therapist/OD team

Therapists, both PT and OT, should get the training to feel comfortable integrating these simple tasks into the interventions they already perform. Next, reach out to optometrists in their area. This relationship will be beneficial for both the therapist and optometrist, but mostly, this will help the patient.

 

(1)Niechwiej-Szwedo, E., Alramis, F., & Christian, L. W. (2017, October 27). Association between fine motor skills and binocular visual function in children with reading difficulties. Retrieved November 13, 2017, from https://www.ncbi.nlm.nih.gov/pubmed/29096178

(2)Palomo-Alvarez, C., & Puell, M. C. (2010, June). Binocular function in school children with reading difficulties. Retrieved November 13, 2017, from https://www.ncbi.nlm.nih.gov/pubmed/19960202

(3)Thompson, B., McKinlay, C. J., Chakraborty, A., Anstice, N. S., Jacobs, R. J., Paudel, N., . . . CHYLD, T. E. (2017, September 29). Global motion perception is associated with motor function in 2-year-old children. Retrieved November 13, 2017, from https://www.ncbi.nlm.nih.gov/pubmed/28864240

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Convergence Tasks for Therapists

The Z axis

As therapists, we recognize the importance of mid-line crossing to help with primitive reflexes.  Reaching lateral outside of the base of support challenges balance and posture.

But to exercise convergence, the therapist must turn their favorite activity into the “Z axis”. This axis is the near-far axis, (referred to as the Z axis in vision) and challenges the convergence and accommodation system.  Many of our favorite activities can be modified just by turning them, to help strengthen the near vision system.

Simple convergence strengthening activities

Clothespins are great therapy tool, strengthening pinch for writing and other tasks. Having a child reach to a distance to retrieve the clothespin then hanging the clothespin on a near string can can help with convergence and divergence. The proprioceptive input of the hand hanging the clothespin on the string will cue the eyes to converge to a point.

The swing adds vestibular and proprioception to the convergence and divergence in this video.

In my clinic, I also use a cup with a straw that patients then put toothpicks in. This task can be graded by moving the cup closer to the child’s face.  This is task also made more difficult by not allowing the kiddo to touch the straw, removing the proprioceptive input,  forcing the eyes to guide the hand more accurately.

 

Amazing creative therapists

Cheerios on a Straw

In the task, the patient puts cheerios on a small coffee stirrer. The hand working at the end of the straw does a great job cuing the eyes to converge. Just make sure the straw stays in at mid-line.

Ball in a Tube

In this task, a 4 ft florescent bulb protector ($4 at Home Depot) is cut in half with a ping pong ball put inside. I then placed stickers on top of the tube. The patient has to align the ping pong ball under the the sticker. In standing? Even better. Balancing on a balance board? Even better!!!

As a bonus, the scrap end of the tube become a great “light saber” for popping bubbles to work on tracking and eye hand coordination.

Thanks to therapists that I have met

The weeks I spend traveling are exhausting but the energy of the people I met help me stay motivated. Thank you to all the therapists and teachers and others, that I have met.

 

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Sensory Modulated Postural Dysfunction

Posture and Vision

The magnocellular tract plays an important role in posture. It provides visual information that allows for spontaneous adjustment of posture and muscle tone as the environment changes. Integration of vestibular information with this visual information helps keep us stable when are moving.

Think of standing on a boat gently pitching to and fro on the water. As the boat rock, the muscles of ones legs, trunk, and neck all compensate and adjust to allow you to stay standing. Imagine how hard it would be to do this if one were blindfolded. It would be much more difficult if the brain was unable to get accurate data about the changes in horizon and the incoming waves.

Sensory Modulated Postural Dysfunction

SMPD is one of the subtypes of sensory dysfunction described by the Star Institute. Marked by postural weakness and decreased stamina (what we may have described previously as “low tone”), these children have difficult times sitting up tall and may demonstrate a head-forward, flexed posture with shoulder rolled forward and possible scapular winging. They may have weak hands and present to OT for difficulty with handwriting or visual motor integration. In optometry, they call this postural dysfunction or other terms.

Posture is Vision Is Posture

The link between posture and vision is very important. Decreased visual acuity or decreased magnocellular awareness can cause the brain to get poor information about the body’s position in space and not allow for appropriate muscular corrections as the environment changes and the child moves.  The vestibular system as well requires visual input to allow for correct adjust adjustment of posture. We might observe this as a clumsy child or a child with weak posture.

As therapists, it is important that we make sure our young patients have a full and complete eye exam as we begin to address postural weakness, visual motor integration and handwriting problems. An uncorrected visual system will make treatment very difficult. But an appropriate visual system becomes a powerful tool to help correct these problems.

Vision as a Postural Tool

It is possible to make use of the powerful magnocellular system to help with posture. The addition of prism or binasal occulsion during a typical treatment for postural problems and “low tone” can alter the perception of visual space. Base down prism will shift visual space upward, making the head go up. When the goes up, the trunk moves into more extension. The brain quickly makes adjustment to the body based on the altered visual space.

Can they see?

I continue to find children with a full team of professionals: PT, OT SLP, ABA, pediatricians, etc,  that have not had an eye exam. Know the ODs in your town that perform comprehensive binocular vision exams and make sure your kiddos can see !!

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“When should we see no head movement during visual tracking?”

When should they hold their head still…

The development  of the visual system in children is much discussed. The AOA offers time lines which have development of eye movement continuing to improve at 36 months. This development is dependent upon many factors including the development of the brain as whole and the vestibular, and proprioceptive systems. The development of these systems is inter-dependent. Problems in the visual system will affect development of the vestibular and other systems and impact the developmental movement sequence. This is why the first eye exam is recommended at 6 months of age.

In the birth to 3 three year old, developmental delays would most likely include tracking and saccades problems, particularly when neurological problems (seizures, anoxia, CP, etc) are present. As therapists, our treatments should should stimulate as many sensory systems at possible, including vision.

Eye Movement norms

The best information on the development of eye movement accuracy comes from the NSUCO Ocular motor norms. The NSUCO protocol looks at ability to perform the movement, accuracy of the movement, amount of head movement present and the amount of body movement present during the testing of tracking and saccades. Each of these skills is rated 1-5 with each score defined in the above referenced article. This is the standard way saccades and tracking are quantified by ODs. Each movement would include 4 numbers describing the child ability to perform the movement. This is a somewhat subjective test, much as our manual muscle testing is somewhat subjective. It is most important for the therapist to recognize the errors and refer to the doctor for scoring, then be able to interpret the score as provided by the doctor.

The norms begin at age 5 and support the idea of a constantly improving ocular motor system until full maturity at the age of the 10. The paper further references minimal standards from age 5 to 10 to help identify less than age appropriate eye movement accuracy.

The Therapist’s job

We should be screening these eye movement on all of our patients. Children with developmental delays have a high incidence of ocular motor problems which affect balance, reading, spatial awareness, fine motor and visual motor integration development. These ocular motor problems are influencing the outcomes of our interventions so being testing them should be a part of every OT and PTs evaluation process.

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Assessment and treatment of Saccade Problems

Saccades – The Quick Movement of the Eyes

Saccades are quick short movements of the eyes. The cavemen used them to quickly assess the environment and see where a threat (or dinner) might be. We use them now for reading, in a series of quick movements and fixation. We also use saccades to update changes in our environment, so they are influenced by peripheral awareness.  They help build a spatial map of the environment. The movements are involuntary and triggered by changes in the spatial environment.

One can look for inaccurate saccades associated with TBI, concussions and strokes. Inaccurate saccades are also associated with most binocular vision problems, like convergence insufficiency.

Measuring the Saccade Problem

Saccades testing can show a therapist overshooting or undershooting, but objective measurement helps set goals.  We use the Developmental Eye Movement test. The DEM provides good objective data concerning eye movement accuracy.

The Developmental Eye Movement test (DEM), is a standardized assessment of saccade accuracy. It is standardized for 5-13 year olds. An adult version is currently being developed and tested, but testing indicates values for a 13 year old are generally valid for an adult. 

The DEM has 4 parts, all involve the timed reading of a list of numbers. The first part is sample of horizontal numbers used to insure the patient can see the text adequately. In the next section, two vertical columns of numbers are read and timed with errors noted.  There are two vertical tests with the times added.

There is the final horizontal test which present horizontal lines of unevenly spaced numbers, which the subject reads while being timed with omissions and substitutions noted.

Times are compared to norms based on age or grade percentiles, They are then used to derive a ratio of horizontal to vertical times that help to identify the cause of the errors, either automatically (subjects ability to call out numbers) versus ocular motor difficulty.

The test is quick and correlates well to reading problems.

The DEM is not perfect as the person must be verbal and recognize numbers. Frequently the task of reading out loud produces a lot anxiety for children that have problems with the task also. Observation of behaviors during the DEM and the reading can also give some insight.

The tester should note…

  • does the child hold the material very close to his face ?
  • …or far?
  • does he squint or rub his eyes during the assessment?
  • does he use his finger to follow the letters?
  • does he move his head during testing? This is very telling as using head movement rather than eye movement slows fluency and saccade accuracy.
  • are there long pauses at the beginning of a new as the child attempts to find the correct line
  • does accuracy of words get worse as the reading continues or does the child use context to fabricate the end of the sentence?
  • Does he turn his head to the left or right?

Following reading, I ask some specific questions if the child had difficulty to help identify what the child is seeing. These questions sound crazy, but make perfect sense to child with saccade or near vision problems.

  • do the words move when try to read them?
  • do you see double?
  • do they blurry then clear then blurry?
  • do they appear to float?

Sometimes the children have a hard time describing just what they see. Parents are often very surprised at the responses to the questions. The child did not know that everyone does not see that way.

Treatment

The treatment for saccade problems, like all ocular motor problems, assumes the child is in best corrected visual acuity.

I also use a sheet or graph paper with random dots for the children to draw small , vertical lines through.

The Hart Chart Decoding activity is also a good task.  This task has a grid of letters on one sheet and themed (there’s SpongeBob and Sports, and others)secret messages on another. Each letter in the massage corresponds to a column/row combination that the child counts to find the letter. Initially the child is allowed to use his finger to help count the rows and columns, but as they get better at the task, the finger is no longer allowed.

EyeCanLearn.com   is an amazing website with vision games and printable with saccade activities.

Having a child read the first letter of words in a paragraph can improve saccade accuracy as well simple vertical strips of letters that can be more further apart. The therapist can add a metronome to these tasks to help increase the pace.  Add balance to these task to increase the challenge of the brain and visual system.

Saccade strips are two strips of paper with vertical letters. The patient reads the letters left to right and top to bottom. Start with the strips close together then separate them as the the patient gets quicker. Remember to keep the head still, even if the therapist has to help!

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Balance and Vision

 

Two Visual Pathways

The focal, central or Parvocelluar visual system is called the “What” vision system. It is responsible for object identification. It allows us to focus on a specific object in the visual field. This information is interpreted in the occipital lobe.

The ambient/peripheral or Magnocellular visual system is the “Where” system responsible for spatial information, balance, coordination and peripheral awareness. This information is shared with the occipital lobe, in addition to links to the cerebellum and balance areas of the brain. Functional MRI shows this information actually reaching 99% of the cortex. Using ambient vision, we can automatically change our posture and gait to walk uphill or protect ourselves from falling over as someone bumps into us.

Functionally, these two systems allow use to look at the road ahead of us (focal vision) and be aware of the car to our left(ambient). It also allows us look at the TV but be aware of where the door in the room is. It allows us to be focused on a word in reading, but still make accurate saccades to the next word.

Notice what happens to the people attempting to walk through the tunnel.

Notice how the people in the tunnel are leaning to one side. The tunnel walls have confused their ambient vision system and affected the gait and balance.

A tool for rehabilitation…

Frequently this system can become faulty following a neurological event. In a condition called Post Trauma Vision Syndrome”, patients become over-centrally focused. This is seen clinically as decreased balance, decreased reading accuracy and poor spatial awareness a midline shift or toe/heel walking.  The patients also report becoming “over-stimulated” by visual information.   A visual field done a patient with this condition might look like this

peripheral loss

This is one eye, but the other may look the same. Notice the reduced periphery that might not show up in typical in-clinic screening of visual fields.  This visual field test is called a Goldman 30-2 and is done on each eye.  It  should be a standard part of the assessment of all of the post-TBI/CVA patients.

Improving Ambient Visual Function

To improve function of the ambient system, binasal occlusion may be added to a patients glasses with or without mild base in prisms.  How does this help?

A person that is over-centrally focused has a difficult time seeing the entire word. They tend to see letters rather than the whole word which greatly reduces reading fluency and comprehension. Saccades also become less accurate due to the decreased awareness of the line of text  making the person lose their place frequently.

This can also improve posture and gait. As the brain becomes more aware of the ambient visual system, it is better able to correctly adjust gait and posture. Remember the tunnel?

Optometrists that offer this type of service are involved in neuro-optometry. The organization is called the Neuro-Optometric Rehabilitation Association. This is a multi-disciplinary organization that was started by ODs who wanted to understand brain injury better and exchange information with other providers of care in the  TBI community like OTs and PTs. There is a provider list on their website to help you find a NORA optometrist in your area.

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