Visual Dysfunction As RD & LD



There are may ways our vision can get in the way of reading. Not everyone who has a reading or learning disability has troubled vision, but everyone whose vision is significantly impaired or labored will have their reading impacted accordingly. Errors in visual signal acquisition (vsa) or visual signal processing (vsp) can occur for a great many reasons, but they all can be generally summarized as follows (some may argue the finer points, but you’ll get the idea):


  • • Extraocular muscle trouble. Each eye is surrounded by six small and high-performance muscles acting as a servo mechanism to direct the eye alone, and then with it’s twin, to exactly where the brain tells it to go.
  • • Anatomical irregularities. The eye may be partially unable to function due to congenital defects or injury.
  • • Disease. The eye is temporarily or permanently partially unable to function due to infectious, degenerative-genetic, or autoimmune disease.
  • • Accommodative disorders. That is, problems with acquiring and maintaining good focus on a target, or signal. The eye struggles to focus and if it achieves it, it struggles to maintain it.
  • • Refractive errors. Myopia, hyperopia, astigmatism, anisometropia, antimetropia, amblyopia.
  • • Strabismus and amblyopia. Eye turns inwards, outwards. Single eye, or both.
  • • Visual signal processing challenges:
    • • Visual Discrimination
    • • Visual Memory
    • • Spatial Relationships
    • • Form Constancy
    • • Sequential Memory
    • • Figure-Ground
    • • Visual Closure
  • • Integration problems. SRD/Dyslexia. Phoneme and grapheme, that is symbol, awareness. Dyseidesia. Dysnemkinesia (visual-motor). Does not apply to dysphonesia unless the child is reading text aloud.
Some examples:
  • • See the ‘Background‘ documents.
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  • • It is also interesting that Dr. Granet (ophthalmologist who promotes VT-like treatment without acknowledging that this was developed by optometry, and furthermore denies that it is ‘VT’) was the author of an article “The Relationship between Convergence Insufficiency and ADHD” which was published in Strabismus, 13:163-168, 2005. In the conclusion, he states “We report an apparent three-fold greater incidence of ADHD among patients with CI when compared with the incidence of ADHD in the general US population(1.8-3.3%). We also noted a seeming three fold greater incidence of CI in the ADHD population. This may simply represent an association and not a causative relationship. Until further studies are performed, however, patients diagnosed with ADHD should be evaluated to identify the small subset that may have CI – a condition that responds well to treatment at home”. Also Granet states that “Reading discomfort can be related to uncorrected refractive errors and to disorders of ocular motility, binocular function(especially convergence), or accommodation. If eye conditions are diagnosed at the time of the visit, they should be treated appropriately; treatment may include glasses for refractive error or convergence exercises for convergence insufficiency.”(With thanks to Dr. Richard Laudon)
  • • Visual Dysfunction as ADHD:
  • • Vision-related learning trouble: