Visual Perception

Of visual perception

There are many assumptions made about a student’s performance on visual perception tests. After all, these tests give norm’ed results which can be helpful in goal making and identifying a potential cause for an academic problem.

But do the results actually reflect visual perpetual skill?

Many factors can hamper the reliability and validity of visual perceptual testing.

  • Visual acuity-is this patient in best correct visual acuity? Have they had an eye exam and been prescribed the appropriate glasses? Do the glasses fit well to allow for the intended benefit?
  • Binocular vision skills?-Poor binocular vision skills can result in double vision and blurred vision up close which can affect the results of visual perceptual testing?

These two factors, when not corrected, make for a “garbage in-garbage out” situation and taint the results of the testing, increasing the likelihood for invalid results in the patient.

Imagine putting a glove on a patient then asking that patient to identify coins that they are holding in the gloved hand. They would have a difficult time doing this, not because of an inability to process the feel of the coin, but because the stimuli to be interpreted is muted. It becomes difficult to process to the correct conclusion when the initial stimulus is faulty.

Behavior and cognition matter too

With best corrected acuity and good binocular visual skills, other factors, such as attention can play a role in visual perceptual testing. Common visual perceptual tests can take as long at 45 minutes of monotonous testing making even the most attentive children bored and possibly affecting results.

Most visual perceptual tests are designed so the child with a visual perceptual problem misses three consecutive items in a section, then advance forward to the next section. The pattern is irregular (child misses one item then 3 correct then misses two items, then one correct) perhaps attention is playing a role in the test results.

Visual Percetual Testing

In my clinic, I do not test visual perception until after binocular vision issues have been corrected and the patient is in best corrected visual acuity.

With these things in place, you will find visual perception intervention much more effective and testing will be more valid and reliable.

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“Is it a vision problem?”

Does this child have a visually-based problem?

Our children present with a vast array of problems affecting their development and academics. Sensory problems, trauma, autism, behavior, ADHD and the list goes on. Our children get assessed by OTs, and PTs, neurologists, neuropsychologists, and pediatricians. But did they have an eye-exam? A complete eye exam? Only 40% of children have had their eyes examined by an eye doctor. (1) That leaves all of those children potentially walking around with vision problems affecting their academic and developmental development. Meanwhile, we attempt to teach them catch a ball or write the alphabet or button a button.

“Does he need an eye exam?”

YES!!! Every child, regardless of academic performance or other diagnosis, needs a complete eye exam with a binocular vision assessment and cycloplegic dilation, even if the child has never complained about their vision.  Many times, when a child is assessed with the Convergence Insufficiency Symptom Survey, they learn that they are not supposed to see “words moving” on the page or see double when they read. They had symptoms and were not even aware. Most children with ocular motor or near vision problems will read letters on a chart without difficulty. 20/20 means only that each eye has good acuity. It does not tell us how well the eyes are working together or how hard the eyes are working to make a 20/20 acuity. Only a complete eye exam with binocular assessment and cycloplegic dilation can give the whole picture.

“Is this is visually-based problem?”

There are many signs a child is having a visual-based problem.

  • Eye rubbing
  • unexplained headaches
  • poor handwriting
  • poor reading skills that do not improve with tutoring
  • head turning or tilting when reading
  • closing one eye while reading
  • poor visual motor integration that does not improve practice
  • poor balance or motion sensitivity
  • Diagnosed ADHD that does not respond to medication
  • unable to catch a ball
  • letter reversals
  • visual perceptual problems
  • spacing and size problems during handwriting tasks
  • fine motor delays
  • poor depth perception

These problems maybe mis-diagnosed as things like dyslexia or ADHD and even be treated as such without success for many years.

“Who do I send them to, to make sure they a complete eye exam?”

A good place to start is College of Optometrists in Visual Development. These doctor specialize in the assessment and treatment of eye movement disorders and near vision focusing problems that could be affecting academic performance. You can your local COVD doctor with the search tool on the site. One might also look for an optometrist that specializes in pediatrics or binocular vision.

When an appointment is made, be specific about symptoms and ask for a “binocular vision assessment”.

Every child

Every child needs a complete eye exam. Parents may have many reasons to not get this dome, but you cannot teach a child read or write, or catch a ball that cannot see.

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1.Children’s Vision Screening and Intervention. (n.d.). Retrieved from https://nationalcenter.preventblindness.org/childrens-vision-screening-and-intervention

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

Vision Rehabilitation Course Companion

Resource Flash Drive

 

I have created a flash drive of resources to further the experience of my live course and webinar.  It is a collection of  web links and PDFs designed to make implementation of the presented course information easier. Click on the picture to get a better look at what is included.

 

The cost of this add-on is $20 USD and you can click here to order .  I will then send you a 128mg flash drive with the all stuff!!

Click for HTML references from the course.

 

Common Birth to 3 Vision Conditions

Vision Birth to Three

The visual system at birth has a lot of development to do. The early eye exam (6 months to one year) should find anything that may impede this development.

Common Birth to 3 vision problems

Common Birth to 3 Eye problems Pathology Acuity Prognosis Functional Problems Modification
Coloboma failure of the halves of the eye to join completely inutreo, may affect pupil, retina or lid varies depending of retinal damage stable condition glare problems if pupil is affected and retina is functional, reduced bincular depth percpetion sunglasses, motor practice
Optic Nerve Hypoplasia decreased evelopment of the optic nerve, usually assocaied with midbrain/endocrine problems varies from minimal affect to near blindness, possbile field cut, possble nystagmus stable condition Delayed motor development due to reduced visual input.   Refer to TVI at 3 yrs old. vestibular and motor facilitation tasks.
Retinopathy of Pre-Maturity scarring related to excessive blood vessel growth during prolonged O2 exposure in premature infants varies by amount of scarring stable condition depends on level of scarring, may be no delays related to vision based on acuity
Corticol Visual Impairment lack of vision due to visual pathway damage/failure to develop Usually not 100% blind stable condition near blindness, refer to TVI, use contrasting colors, movment and work peripheral to central to investigate amount of vision. Referal to TVI is important for school readiness.
Accommodative Esotropia medial eye turn due to extreme farsightedness 20/20 with glasses in place, eye turn also corrects with glasses improves, but child will remain in glasses throughout life none with early correction, amblypoia without correction glasses should be comfortable and worn at all times.
Infantile Esotropia medial eye turn not related to generally reduced due to amblyopia, may improve with correction varies, tx by surgery vs VT vs Botox reduced motor development per doctors order concerning patching, facillitate motor improvement
Amblyopia reduced acuity due decreased visual pathway development  due to prolonged suppression or lack of stimulation to visual pathway varies, 20/200 or worse to 20/50 depending on patching complaince and glasses wear compliance. may improve with compliance of tx and glasses wear, binocular vision therapy reduced motor dev., head turns, decrease binocular depth perception. Brain with compensate in time motor dev facilitation, exercise amblyopic eye if currently patching, binocular vision activities
Strabismus eye mis-alignment at rest, corrected with surgery vs VT vs Botox varies, generally reduced due to amblyopia varies greatly. Long term, brain adapts to suppression of the turned eye reduced motor dev, self-esteem, self conscious of turned eye, reduced binocular depth perception eye exercises per doctors order, facilitate motor development

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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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Letter Reversals

Letter reversals are frequently an area of concern for parents as their child begins to learn writing and reading. Reversals are often viewed as a sign of dyslexia and are surrounded by myth. Here are the facts on letter reversals

  • Letter reversals are common and appropriate until a child reaches 7 or 8 years old (second grade).
  • After the age of 7-8, the children who continue to have reversals are the children that are having difficulty with reading(1)
  • Learning letters is the first time a child learns that an item becomes a different thing based on the way it is facing. A cup from seen from one side or the other is still a cup but a “b” seen the other way (“d”) is not the same thing.
  • Visual spatial and left/right body awareness correlated with children having letter reversal problems suggesting that addressing left/right awareness would improve letter reversals (2)
  • Working memory deficits, also found in dyslexia, were found in children with letter reversals, so addressing working memory may improve letter reversals. (3)
  • Children with ADHD tend to have more reversals, possibly related to difficulty in an inability to to suppress the more natural left-right flow of making most letters.

Treatment Ideas

Having the child the pull letters from a bag and identify the letters without looking at them has been a great activity (suggested by Dr. Charles Boulet) and correlated well with children having difficulty with this task that have reversal problems.

Dr. Kenneth Lane OD, FCOVD’s book , Developing Ocular Motor and Visual Perceptual Skills: An Activity Workbook, has an excellent discussion of letter reversals as well as treatment techniques. Presenting p-q-d-b chart and having the child touch “p” and “b”  with right and q and d with the left has proven to be very challenging. This activity include a component of eye0hand cooridnation and saccade accuracy that will further improve binocular vision and saccade accuracy.

The Optomteric Extension Program offers Recognition of Reversals Workbook, also by Dr, Lane (a great bookstore!!). This workbook has more activities for reversals and its only $20.

Calm the panic!!

In a few cases, letter reversals after the age of 7-8 can indicate dyslexia, but there are many other reasons a child may have reversals.

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About the Author

Learn more about this subject in a live course presented by Robert.  Its now available as a webinar too!! Hosted by PESI Education

 

References

  1. Terepocki, M., Kruk, R. S., & Willows, D. M. (n.d.). The incidence and nature of letter orientation errors in reading disability. Retrieved October 04, 2017, from https://www.ncbi.nlm.nih.gov/pubmed/15493319
  2. McMonnies, C. W. (1992, October). Visuo-spatial discrimination and mirror image letter reversals in reading. Retrieved October 04, 2017, from https://www.ncbi.nlm.nih.gov/pubmed/1430744
  3. Brooks, A. D., Berninger, V. W., & Abbott, R. D. (n.d.). Letter naming and letter writing reversals in children with dyslexia: momentary inefficiency in the phonological and orthographic loops of working memory. Retrieved October 04, 2017, from https://www.ncbi.nlm.nih.gov/pubmed/21978009
  4. Levy, F., & Young, D. (n.d.). Letter Reversals, Default Mode, and Childhood ADHD. Retrieved October 04, 2017, from https://www.ncbi.nlm.nih.gov/pubmed/26794673