Myopia, or nearsightedness, is a refractive error whose prevalence has increased over the past three decades, leading to a growing concern and interest among both the public and scientific communities. For years, the only explanation and basis for myopia has been genetic factors. However, the genetic model does not explain the dramatic increase in prevalence. Current research suggests that the increase is also due to environmental factors, such as fewer hours of outdoor activities, early educational pressures requiring intense close work, as well as a lack of exposure to sunlight. One study compared the prevalence and risk factors for myopia in 6 and 7-year old children of Chinese ethnicity in Sydney and Singapore. In another study, a diffuser was placed over the eyes of chicks which caused the eyes to grow excessively myopic. This increased myopia was due to the lack of dopamine which originates from cells in the eye when stimulated by sunlight. One additional study suggested that formula milk, unlike breast milk, lacks DHA and can also result in myopia. The results of these studies suggest that progressive myopia is due not only to hereditary factors but also due to environmental factors. Recognition of these factors may be useful in developing future treatments.
Weissman, J. (2014). Environmental Factors and Progressive Myopia: A Global Health Problem. The Science Journal of the Lander College of Arts and Sciences, 7 (2). Retrieved from https://touroscholar.touro.edu/cgi/viewcontent.cgi?article=1099&context=sjlcas