Refractive error, IQ and reading ability: a longitudinal study from age seven to 11

Area of Science:

• Ophthalmology
• Developmental Psychology
• Educational Psychology

Background:

• Refractive errors like myopia and hypermetropia are common in children.
• The relationship between refractive errors and cognitive abilities, such as IQ and reading, requires further investigation.

Purpose of the Study:

• To compare IQ and reading abilities in children with myopia, pre-myopia, and hypermetropia against those with normal vision.
• To determine if observed differences are linked to pre-existing abilities or other factors.

Main Methods:

• A population sample of children with varying cycloplegic refractive errors (myopia, pre-myopia, hypermetropia) was assessed.
• Cognitive measures included IQ (verbal and performance) and reading scores.
• Comparison was made with a control group of children without significant refractive errors.

Main Results:

• At age 11, children with myopia and pre-myopia exhibited elevated verbal and performance IQ scores compared to controls.
• Children with hypermetropia showed slightly reduced verbal and performance IQ scores.
• Differences in verbal IQ were not explained by earlier abilities, while performance IQ differences were.
• No significant differences in reading scores were detected between groups.

Conclusions:

• Cognitive differences observed in children with myopia and pre-myopia at age 11 are not solely due to family background or prior ability.
• Refractive errors may be associated with variations in cognitive development, particularly IQ.
• Further research is needed to understand the mechanisms underlying these associations.