Untangling Dyslexia and Vision

Most experts agree that dyslexia is a language-based disorder. Individuals with dyslexia usually have difficulties with specific language skills, in particular reading; however, typically experience difficulties with other language skills as well such as spelling, writing, and pronouncing words. Vision problems can interfere with the process of learning; however, vision problems do not cause or result in dyslexia.

It is important to be aware of the differences between dyslexia and dysgraphia, as the two can appear similar at times. Dysgraphia is the condition of impaired handwriting. Impaired handwriting can impede learning to spell and speed of writing text. Individuals with dysgraphia may have only impaired handwriting, only impaired spelling, or both.

Individuals with dyslexia experience difficulties acquiring and using written language. Many people believe that individuals with dyslexia “read backwards” however this is a myth. Individuals with dyslexia are often times poor spellers because they have difficulty remembering the sounds associated with letters; and forming memories,or mental maps, of words.

Individuals with dyslexia can experience problems:

• Learning to speak

• Learning phonics (letters and their sounds)

• Spelling

• Learning grammar

• Learning a foreign language

• Expressing themselves clearly

• Reading quickly enough to create the “movie” in their mind

• Reading quickly enough to comprehend

Not all individuals with dyslexia have these difficulties. Formal testing is required to confirm a diagnosis of dyslexia.

Dyslexia is considered a primary reading disorder and results from language processing (written word processing) abnormalities in the brain. Children learning to read experience difficulties with sight word recognition, poor spelling and decoding deficits.

Oral language development has been found to play a critical role in learning to read. Unlike speaking, reading and writing do not develop naturally and require active learning. In order to read, individuals must first learn the sound structure of the spoken language and then match the sound to the letter of the alphabet – making the sound / symbol connection.

Dyslexia has been identified as having a strong genetic link. Approximately 40% of siblings, children, or parents of an affected individual will have dyslexia. Although dyslexia is often times inherited, it is possible to have dyslexia in the absence of any family history.

It is important to note that the definition of dyslexia does not include reversal of letters or words or mirror reading or writing, commonly held misconceptions. Studies support that dyslexia is a language-based disorder. Let's look at the English language as an example. English is a phonemically complex language. The English language has 26 letters of the alphabet that create 44 sounds. Research shows that the phonemic complexity of an alphabet-based language, such as English, corresponds to the prevalence of dyslexia. This further points to the linguistic origin of dyslexia, a language-based disorder. Individuals with dyslexia exhibit an abnormality in the word-analysis pathways that interferes with their ability to convert written words into spoken words.

On the surface, dyslexia “looks like” a vision problem. However, visual processing is a higher cortical function. The eyes transmit the image to the brain where decoding and interpretation of the image occurs. Vision is fundamental for reading; however, the brain must interpret the incoming visual images. Outdated theories have linked deficits or defects of the visual system as a cause of dyslexia. Current studies have proven these theories to be untrue. Word reversals and skipping words, which are seen in readers with dyslexia, have been shown to result from linguistic deficiencies.

If there is a family history of learning difficulties, delayed or difficulty in speech or language development, or a pattern of “late readers” in the family it is important to remember early detection is important. Unfortunately, often times learning difficulties are not discovered until the individual experiences academic struggles in elementary school. Academic struggles such as difficulty with reading, spelling, handwriting, remembering words, or performing mathematical calculations. Early detection, prompt diagnosis and remediation are critical to reaching full academic potential.

Accurate diagnosis and treatment require the collaboration of a team of providers that include: parents, educators, pediatricians, neuro-optometrists, audiologists, speech pathologists and neuro-psychologists. Assessment of overall health, vision, hearing and speech are all vital to accurately diagnosing the cause of a learning difficulty and prescribing the appropriate treatment. It is important to note that a screening of any type does not replace a professional assessment. For instance, a vision screening at the pediatrician's office is not as comprehensive or in-depth and a formal eye exam with a residency trained pediatric optometrist. A hearing screening at the pediatrician's office does not meet the requirements of a professional assessment by an audiologist. Your child's healthcare team should be comprised of specialists within their specific areas of expertise and training; these experts can then collaborate and insure that your child receives the best care possible. With early diagnosis and individualized, interdisciplinary treatment strategies in place, individuals with learning difficulties can reach their full academic potential.