Evolutionary medicine: Why does prevalence of myopia significantly increase?

Myopia is characterized by the axial elongation of the eyeball which causes the image of distant objects to fall in front of the retina so that it cannot be brought into focus. Individuals with myopia experience blurred distant vision. Notably, high myopia significantly increases the risk of pathological ocular changes including retinal detachment, glaucoma, and myopic macular degeneration [1]. Myopia prevalence has approximately doubled in the past three decades, and it is estimated that 49.8% of the world population will develop the condition with 9.8% having severe myopia by the year 2050 [2]. Eye growth is regulated by a homeostatic control process. Human infants are born hyperopic with the eyes exhibiting gradual development from visual inputs, eventually reaching emmetropization (Fig. 1A). The majority of our human ancestors were probably slightly hypermetropic or emmetropic, and thus had clear distant vision in order to monitor environmental dangers [3]. EVOLUTIONARY PERSPECTIVES