It is true that squinting is bad for your eyes. However, you will not become strabismus because of often squinting. But you will keep the habit and become the squinting eyes which will affect your eye vision and make you become difficulty in seeing thing correctly. You should better not squint your eyes often.
Squinting does no harm to the eyesight and it is a natural response in order to try to see things clearly when the objects appear out of focus because squinting narrows your vision field so that your eyes can focus more clearly on the objects. But if you squint often, it is possible for you to develop a condition in which the eyes are not properly aligned with each other due to lack of coordination between the extra ocular muscles, in other words, you may become really strabismus. I advise you not to squint often, because it can give rise to wrinkles and lines in your face and squinting a lot can make your eyes puffy.
Well, yes, it can be. So you should pay more attention to. As we know that when you get squinting eyes, it can cause wrinkles around the eyes and forehead. So it can be ugly and annoying. And generally speaking, it can cause many problems, first, it can cause headache, the dry eyes, dark circles under your eyes, even the vision sight. Also, your eyes' muscle becomes stressed because of it. And then it can put stress on the eye muscles and the facial and scalp muscles, causing pain and headache. Anyway, just pay more attention to it. by the way, you may suffer squinting eyes from excessive sunlight exposure.