So many things in the health and fitness world are really just common sense. One such common sense principle is that moving at a steady easy pace in space is relaxing. Think going for a walk outside. At a leisurely pace the feeling of walking past objects makes you feel relaxed. This can also be achieved by going for a bike ride, running, or riding a skateboard. The sciency term for what is going on during this type of activity is optic flow.
This will not only relax you and help you sleep better at night, but also benefits the general health of your eyes. The majority of us spend much of our time stationary looking at stationary things. Even if we do exercise, much of the time we are in one space instead of moving through it. This lifestyle keeps our eyes from practicing the ability to focus or unfocus on objects as we move past them.
Another aspect necessary for optic flow is that the movement needs to be self driven. So if you thought you could get this practice in on your drive home from work or school think again. You body is still stationary in that scenario. To generate this type of visual stimulation you have to be moving yourself past the stationary objects. The speed does not matter as much as the movement so hop up and go for an easy walk or bike ride today when you get home. If you play a field sport this is especially important as you need the ability to focus on movement around you as you move too!