May 15, 2023 By Jeff Anshel, OD, FAAO High glycemic load carbohydrate diets may alter the genetic influence of the growth of the sclera and choroid, which will induce permanent changes in the development and progression of myopia, particularly during periods of childhood growth. Within the eye care community, there is consensus that the cause of juvenile-onset myopia involves genetic and environmental elements. The rise in the prevalence of myopia has been too rapid to be explained by genetic factors alone and thus suggests a substantial role of environmental influences. Numerous studies have demonstrated that near point work is related to myopia. However, all people in industrialized countries must do regular near work during childhood education, yet only a certain percentage of the population ultimately develops myopia. Also, the interaction of genetic and environmental  components alone to create refractive error remains speculative. Perhaps there is something else. For example, little attention has been paid to the role of nutrition in the development and advancement of myopia . . . until now. The Evolutionary Perspective When considering the genetic influence on ocular growth and function, we must first examine our ancestral genetic makeup. Early Homo sapiens lived about 160,000 years ago and are considered to be anatomically modern Homo sapiens.1 We can infer that significant myopia was not likely present in the population since these early humans required clear distance vision to escape predators, find food, and recognize other species members and a host of environmental dangers. Thus, any gene or genes that would produce significant myopia would be lethal and rapidly eliminated by natural selection. Dietary-Induced Hyperinsulinemia and Myopia The diets of hunter-gatherer civilizations are typically considered high protein with moderate levels of fat and low levels of carbohydrate when compared to modern Western diets.2 Additionally, the carbohydrates present in hunter-gatherer diets were typically of a low glycemic index. They are slowly absorbed and produce a gradual and minimal rise in blood glucose and insulin levels compared to the sugars and refined starches in modern western diets.3  The glycemic index ranks carbohydrates on a scale from 0 to 100 according to the extent to which they raise blood sugar levels after eating. High glycemic index foods are rapidly digested and absorbed and result in marked fluctuations in blood sugar levels. Low glycemic index foods, by virtue of their slow digestion and absorption, produce gradual rises in blood sugar and insulin … Continue reading The Role of Nutrition in Myopia Development and Management