Spectacle lenses alter eye growth and the refractive status of young monkeys

The influence of visual experience on ocular development in higher primates is not well understood. To investigate the possible role of defocus in regulating ocular growth, spectacle lenses were used to optically simulate refractive anomalies in young monkeys (for example, myopia or nearsightedness). Both positive and negative lenses produced compensating ocular growth that reduced the lens-induced refractive errors and, at least for low lens powers, minimized any refractive-error differences between the two eyes. These results indicate that the developing primate visual system can detect the presence of refractive anomalies and alter each eye's growth to eliminate these refractive errors. Moreover, these results support the hypothesis that spectacle lenses can alter eye development in young children.