Myopia-What is Old and What is New?

The recent "boom of myopia," described predominantly for East Asia, is assumed to result from increasingly demanding education programs that include extensive near work (and perhaps also extensive use of computers) and little exposure to bright light as found outdoors. Already in 1892, Hermann Cohn stated that the prevalence of myopia is related to the educational level which is related to the economic status of a country. It is not much appreciated that the rates of myopia were already high among school children in central Europe in the middle of the 19th century, as described by Hermann Cohn. From extensive research in recent times, three major approaches have emerged to interfere with myopia progression in children: (1) promoting exposure to bright light and enforce outdoor activity, (2) adapting/improving optical corrections and visual behavior to generate inhibitory signals for eye growth in the retina, and (3) applying atropine eye drops at low doses. However, Hermann Cohn had already proposed that low luminances during school work promote myopia development and requested that lighting in the classrooms needs to be at least "10 meter candles" (equivalent to an illuminance of 10 lux). Different from today, he explained the link between low light and myopia by shorter reading distances that he observed at low luminances of the reading surface (<<1 cd/m). He suggested that short reading distances should be avoided in children and described several devices to control them. He further suggested that reading duration should be limited and urged myopes to choose professions that do not involve extensive near work. He also studied the effects of atropine against myopia but concluded that the side effects make it less useful than simply "3-4 weeks without reading." In summary, a number of his findings were re-discovered today, but they are now much better supported by data, and their interpretations have changed, at least in some aspects.