The underachieving child.

Visual factors in specific learning difficulties (SpLD) are reviewed. People with SpLD fail to achieve at a level that is commensurate with their intelligence. The commonest SpLD is dyslexia, which usually results from phonological processing/decoding deficits. Additionally, there are several optometric correlates of SpLD which may, in some cases, contribute to the learning difficulty. These correlates include binocular instability and a low amplitude of accommodation. Some people with reading difficulties and perceptual distortions/eyestrain can be helped by individually prescribed coloured filters. A visual processing anomaly is also often present in the form of a deficit of the transient visual system. The role of the optometrist is discussed.