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2012-13 Texas FocusThe Neurophysiology of Reading with Low Vision

March 31, 20138:30-10:00 AM or10:30 AM – 12:00 PM

Presented byDr. Bill Takeshita, O.D. FAAO, FCOVDCenter for the Partially Sighted, Los Angeles, CAdrbillfoundation@gmail.com

Developed forTexas School for the Blind & Visually ImpairedOutreach Programs

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Neurophysiology of Reading with Low Vision – Takeshita, 2012 0

Vision and Reading

Bill Takeshita, O.D., F.A.A.O., F.C.O.V.D.

drbillfoundation@gmail.com

Acuity Versus VisionGood acuity is not synonymous with good vision

A person with 20/20 vision may have reading difficulties

20/20 sight only describes whether a person can read a letter 3/8 inch letter from 20 feet

Figure 1 Photo of Feinbloom acuity

Neurophysiology of Reading with Low Vision – Takeshita, 2012 1

Review of Anatomy

Figure 2 Diagram of perspective of eye

The CorneaThe cornea is the clear transparent tissue that covers the front of the eye. It has the most diffracting power of the eye which allows light to focus into the eye. The cornea has the highest number of pain fibers per square millimeter. Thus, injury to the cornea is very painful.

Figure 3 Image of the inside of the eyeball seen in a vertical section.

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Cataracts

Figure 4 Photograph of an eye showing a cataract.

Congenital Metabolic disorder Trauma Diabetes Age related

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Retina

Figure 5 Drawing of the inside of the eye showing macula.

Rod cells in periphery of retina provide night vision, peripheral vision, and sensitivity to motion Cone cells are located in the center and are responsible for identification, color, and

identification vision

The Optic Nerve

Figure 6 Photo of back of the eyeball and the optic nerve.

Accumulation of nerves from the rod and cone cells Over 125 million fibers make up the optic nerve 20 % of the fibers control motor skills

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Visual Pathway

Figure 7 Photo of pathway

The Brain Processes Information

Figure 8 Image of brain showing activity in darker region.

Two thirds of the brain is involved in the process of vision Occipital lobe Parietal lobe Temporal lobe Frontal lobe

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Brain When Reading

Figure 9 Two images showing a diagram of occipital lobe and angular gyrus stimulated

Eidetic and Phonetic Reading Eidetic reading occurs in the Angular gyrus for whole word or sight reading of words. Phonetic reading occurs in the Wernicke’s area and enables decoding of words.

Reading Acuity (Clarity)

Figure 10 Photo of reading acuity card Game card

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Accommodative Focusing Skills

Figure 11 Photograph of flippers

Treatment Reading glasses, bifocal, and progressive reading glasses Vision therapy is recommended for people under the age of 45 years. Large print books

Video Magnifiers

Figure 12 Photo of a video magnifier

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Fixation Skills

Figure 13 Photo of angle kappa

Eye Movement / Tracking Skills Saccadic tracking eye movements are shifting from one word to another Pursuit eye movements involve following a moving target Foxal cgbm degs cmar podhb lefms ilm gslf asklg ijlah amcxzje woikl asnmv onai ainoa

spqem mxdql harud tskcis kavte lauc mviwx wxliv xynm eys aldgzev.`

Treatment

Figure 14 Two pictures representing vision therapy

Binocular Vision Disorders Reduced ability to coordinate both eyes together as a team Double vision (diplopia) Eye-strain (asthenopia) Headaches Words appear to jump on the page 42% of patients with TBI

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Strabismus

Figure 15 Photograph of esotropia and exotropia

Esophoria and Exophoria Tendency of the eyes to cross or turn outward. You do not physically see the eyes cross or turn outward. Often is more symptomatic as compared to the person with strabismus.

Treatment Glasses with prisms to eliminate double vision and to improve eye muscle strain. Vision therapy to improve convergence and divergence skills. Patching of one eye can be helpful until vision care can be provided. Large print books will reduce the eye muscle demands.

Peripheral Vision Loss Blind spots in either the central or peripheral field of vision will affect reading Loss of peripheral vision on the right side affects tracking skills from left to right. Peripheral vision loss of the left side affects how easily one can track from the end of one line

to the beginning of the next. Central blind spots affect the clarity of sight. 38% of patients with TBI have visual field loss (Suchoff)

Blind Spots Ma y ch ld en wh ha e ce tr l vi io pr bl ms ha e di fi ul y re di g qu ck y. I be yo ca no re d th s

as qu c ly as yo wo ld li e.

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Hemianopsia

Figure 16 Photograph of hemianopsia

Tunnel Field

Figure 17 Photograph of tunnel visual field

Treatments Prism glasses Eccentric viewing training Adaptive technology with magnification scanners Teach to read by rotating paper or to move the paper rather than the eyes

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Low Vision Spectacles

Figure 18 Photograph of high power spectacles

Magnifiers

Figure 19 Illuminated hand mags

OCR Scanning Systems

Figure 20 Photograph of Freedom Scientific SARA

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A.B.I.See Eye Pal Solo

Figure 21 Photograph of eye pal solo

Kurzweil KNFB Mobile

Figure 22 Photograph of Kurzweil KNFB Mobile Reader

Audio Books BookShare.org National Library Service Recordings for Blind and Dyslexic RFBD.org GW Micro Book Sense Humanware Victor Reader Stream

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Braille

Figure 23 Photograph of Braille Note

Visual Perception Skills Visual discrimination: Ability to perceive that similar objects are actually different Visual memory: Ability to remember what has been seen Visual spatial relations: Ability to recognize that an object is rotated or flipped Visual figure ground: Hidden picture Visual motor skills control how vision guides body

Vision Therapy Does NOT: Cure medical conditions such as autism, attention deficit disorder or learning disabilities Strengthen eye muscles. Vision therapy increases the neuro-muscular innervation between

the brain and the muscles of the eyes Eliminate the need for glasses

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Texas School for the Blind & Visually Impaired

Outreach Programs

Figure 24 TSBVI logo.

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"This project is supported by the U.S. Department of Education, Office of Special Education Programs (OSEP). Opinions expressed herein are those of the authors and do not necessarily represent the position of the U.S. Department of Education.

Figure 25 IDEA logo

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