Researchers at Harvard University have shown that over time, prolonged exposure to blue light can cause damage to the retina at the back of the eye, which may lead to age-related macular degeneration (AMD) and possibly other serious health and vision problems. How significant a health problem is spending time watching cell phone, tablet, and computer screens?

There can be difficulties when too long a period of time goes by with light of a singular frequency. This is the nature of the difficulty, it is somewhat akin to the phenomenon of having extreme light intensity that bleaches out the cellular response and creates an afterimage in the visual field, as in seeing a flashbulb go off in close range and then being blind for a time. That can take a toll in causing disarray physiologically and then this can stir up inner concern by the subconscious mind, which will go looking for what it knows about vision problems and may well find old karmic shadows that will re-echo and remind the person of times of being sightless, having reduced vision that led to disaster, and other quandaries from having an infirmity involving the visual acuity. This reawakening of karma can compound things—this is primarily the villain here. There are a series of events that can conspire to take an ongoing insult from a fairly benign problem in the short term and then with long-term experiencing, build it into a serious physical problem that can become chronic and take on a life of its own. It is, in effect, directly analogous to an ergonomic injury involving a physical manipulation done over, and over, and over, and over, that causes strained joints and tendons and can cause chronic inflammation with an eventual impairment of function if too prolonged without rest. This is one of the underlying truisms in the saying, "Variety is the spice of life," because variety brings change and this allows varying faculties to be rotated into use and that change will allow a rest period for those muscles and bodily systems pressed into high gear for the previous activities. This creates a life of healthy balance where there is time for recreation, time for fun, time to stand down and simply rest and recuperate. That is the guiding principle to be kept in mind here as in all life activities.