If this is about your child, here is the one thing to know: children do not grow out of a squint.
When a child's eyes point in different directions, the brain receives two conflicting images. To avoid double vision, it simply switches one eye off. That eye is still healthy, but because the brain stops using it, its vision never develops properly. This is amblyopia (lazy eye) — and after roughly the age of 8, it becomes very difficult to reverse. The good news is that early treatment is usually not surgery. Caught in time, many squints are managed with glasses and patching alone.
For adults, squint correction is not just cosmetic. It can eliminate double vision, restore proper depth perception, and remove something that quietly affects interviews, teaching, client-facing work and social confidence. There is no upper age limit for squint surgery.