Hereditary Myopia

THE THEORIES concerning the etiology of myopia are many and varied and have undergone a change as time has gone on. Von Graefe suggested that myopia was caused by subacute inflammation of the choroid and sclera. This theory has been disproved microscopically by the fact that the hyperemia, exudation and cicatrization found in myopia are only processes of repair which follow stretching and lacerations of ocular tunics. In 1610 Kepler stated the belief that the influence of near work, which requires accommodation and convergence, was an etiologic factor. Donders disproved this basic principle by showing that the highest grades of myopia may be found in illiterate persons and in people who never engage in close work. This theory was also disproved by Holm,1who made a thorough study of ocular refractive errors in the natives of Gaboon, French Equatorial Africa, one of the most ancient strains of the Negro