Can crossing your eyes for fun cause bad vision?

No, crossing your eyes for fun does not cause bad vision. Crossing your eyes is a common habit that is generally harmless. It is a voluntary action that involves moving your eyes inward, so that the pupils are no longer aligned. Although it may look strange, it is not known to cause any lasting damage to your vision.

However, it's important to note that excessive eye crossing, or strabismus, which is a condition in which the eyes do not align properly, can lead to double vision, eye strain, and other vision problems. If you have persistent crossed eyes or any concerns about your vision, it is always a good idea to consult an eye doctor.