Vision deterioration causes

Vision deteriroration causes
Someone's vision deteriorated as a result of that he is looking at a screen all day, without periodic rest and active watching around.
And for someone, it happened because he was scared of something and due to mental stress there was a spasm of the eye muscles and vision deteriorated.
For someone, vision could deteriorate because as a child he constantly saw how his parents argue with each other and the child was constantly under stress.
Our eyes and eye muscles are very sensitive. Much more sensitive than the skin of our hands. And in case of any dangerous situation, our eye muscles get tensed and if a person doesn`t know how to relax them it can cause constant tension of the eyes and vision deterioration. Because only Relaxed eyes see clear.
There can be many reasons and not a single doctor can tell you what the real reason is.