Developmental dyslexia results from cerebral dysfunction, manifesting itself as a specific learning disorder for reading, spelling, and writing. Children so afflicted have otherwise normal intelligence. Early detection will prevent secondary emotional difficulties. Many of these children are brought first to the ophthalmologist because eye trouble is equated with inability to read. He is therefore in an excellent position to screen children for reading disabilities. Simple questions and tests are recommended to assist him. Past studies indicate that poor readers often have mixed dominance. Our studies of 105 children show that mixed cerebral dominance occurs in a significant percentage of good readers as well as dyslexic children. We conclude that attempting to change mixed dominance as a method of treatment for dyslexia is not neurologically sound.