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REVIEW

Others argue that the full correction of any heterophoria would reduce visual fatigue during reading. According
to this hypothesis, small heterophoria would result in compensatory effort to maintain adequate binocular vision,
and should therefore be completely corrected using the appropriate prism. 64,65 However, many authors refute this
hypothesis and do not recommend the use of prisms because it does not improve reading performance. 66,67 The re-
ported beneficial effects could be attributed to a placebo effect. 66,67 To date, there is no clear scientific evidence to
encourage the use of prisms to improve reading in children with learning disabilities. 4,6,20,21,57,66,67

DISCUSSION
Dyslexia is a neurobiological disorder of the decoding and comprehension of written language. More specifically, it
is a disorder in the sound-structure process of written or spoken language (phonological disorder). It is a persistent
6
and chronic disorder whose causes are multifactorial and influenced by genetics. 6
Oculo-visual impairment can interfere with the learning process for reading, but does not cause dyslexia or learning
disabilities. In fact, although vision is fundamental for reading, the brain must analyze the visual images transmit-
ted. Statistically, children with dyslexia or associated learning disabilities have the same level of visual function
and eye health as children without these conditions. 3,8,18,19 To date, there is no scientific evidence proving that visual
therapy, training glasses, pursuit and saccade exercises, perceptual exercises, magnifying glasses, coloured lenses or
prisms can significantly improve the reading performance of children with learning disabilities. 2,4,6,7,14,20-22,57,68 These
approaches can give false hope to parents and other stakeholders, and thus possibly delay the use of interventions
with greater potential to benefit the child. In addition, the costs of these therapies are substantial and the time re-
quired to apply them is significant. Studies on improving learning through these therapies are in fact scientifically
uncontrolled or anecdotal. Any proposed benefits would likely be secondary to other traditional educational treat-
2,4
ments often performed in combination with these visual therapies and/or the placebo effect.
CONCLUSION
Early detection of children with learning disabilities and referral to appropriate professionals is essential to provide
the necessary support to these children and their families. It is essential that these children have a complete visual
examination with cycloplegia to ensure that they do not exhibit visual impairment that impairs their visual function
and thus can amplify the symptoms of dyslexia/learning disabilities. These children require a multidisciplinary
approach. In addition to a vision assessment, an assessment of health, development, hearing and, if necessary, a
medical and/or psychological intervention will be required. 4,6,13,14,20,21 Finally, dyslexia and learning disabilities are
complex problems with, unfortunately, no simple solutions. However, it is recommended that all proposed thera-
pies be scientifically justified to create realistic expectations and encourage the child’s development. l

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