Dyslexia was once called “word blindness,” even though vision was never the problem.

A young boy’s unusual reading difficulties helped doctors recognize that dyslexia is not about intelligence.

Reading is more than seeing. It requires the brain to turn letters into sounds, language, and meaning.

October is Dyslexia Awareness Month, making it a good time to revisit an intriguing chapter in the history of language and the brain: how the medical profession came to understand dyslexia. What began as a puzzling disconnect between vision and reading would eventually reveal that reading is far more than simply seeing words on a page.

A Problem With Written Words, Not Eyes

In the 19th century, doctors encountered people who could speak, write, and understand language normally, yet struggled to read. In the 1870s, German physician Adolf Kussmaul gave this puzzling condition an evocative name: Wortblindheit, or “word blindness” (Stollznow, 2026).However, the label was misleading. These people were not literally blind, and their eyesight was often perfectly normal. Their difficulty was with the written word. The mystery was how someone could see a word clearly yet be unable to make sense of it.

Kussmaul’s observations influenced Rudolf Berlin, a German ophthalmologist who studied patients struggling to read despite having normal vision. In 1877, Berlin coined a new term for the condition: dyslexia, from Greek roots meaning “difficulty with words.” The new term shifted attention away from........

© Psychology Today