Getting quality lighting is very important - whether it be at home, school, or work. The reason behind that is pretty self-explanatory, right? Anyway, even if you're using high quality metal switch plate covers, that wouldn't really matter much if the lighting itself isn't good.
If you want to keep your vision healthy, make sure that you have adequate lighting, especially when you're reading something or using your computers. You don't want to unnecessarily add to the strain in your eyes by using faulty lighting, right?
Aside from that, wear eyeglasses (if you have any) and don't forget to rest your eyes for a bit from time to time! :)