Influence of the myopia gene on brain development.

Evaluation of the performance of 17-18-year-old high school students on standard intelligence tests confirms previous reports that nearsighted persons consistently achieve scores approximately eight I.O. points higher than non-myopes. Comparison of tests administered to the same students 10 years earlier suggests that the intellectual gain precedes the development of nearsightedness. Since there is convincing evidence from genetic studies that myopia is an inherited condition, probably transmitted as a recessive characteristic, it is concluded that the myopia gene has a stimulant action on the brain in addition to its effect on the eye. The high frequency of myopia in urbanized societies is explained in terms of an evolutionary adjustment, myopes probably having a survival advantage under conditions of industrialization.