After reaching a certain age, your eyes will start ageing and will perhaps even develop presbyopia or some other eye problem. If you are not able to focus, and if you work in a place where there are dangers to the safety of your eyes, then it is time for you to wear bifocal safety glasses, especially if you have multiple vision problems. When we age, our muscle fibres develop issues around the eyes that make it hard for our eyes to focus on objects. If your job requires you to read while working, then not being able to focus on reading matters becomes a real problem.