Most people can focus and unfocus their eyes on command – it is a normal part of eye care, done to help the body adjust for far-off and close-up objects. It is also a technique that can be used to strengthen the ciliary muscles and help improve vision, especially for those with nearsightedness and astigmatism.
The process is very simple. First, you need to find a place where you can relax and have a good view of the surrounding area. You can even try this in a dark room with a bright light (but not directly in it) to test the effect. Close one eye and focus intently on something close to you, causing your pupils to narrow. Now, open your eyes and unfocus them by looking at something farther away, causing the pupils to expand to the new distance. It takes practice, but it is easy to learn.
Unfocusing the eyes can also be a very helpful way to relieve eyestrain and fatigue, which often occurs when you stare at an object for too long. It can also be useful when you need to refocus quickly for tasks such as driving or reading.
However, not being able to unfocus the eyes on command can be a sign of a more serious problem. In some cases, it may indicate esotropia, or lazy eye, where one eye turns inward toward the nose. It can lead to headaches, eye fatigue and blurry vision if left unchecked. It can also prevent your eyes from working together properly to perform tasks, which is why many adults end up with prescriptions for reading glasses.