The LASIK flap adheres within days to the underlying corneal bed. I have seen flap movement within the first 3-4 days after LASIK in 1-2% of patients. If the flap malposition is immediately recognized and treated, the flaps are very easy to reposition in this early post-op period. I have not seen a flap displaced after 4 days post-op. I would assume that a LASIK flap could be dislocated by significant direct trauma to the eye for many weeks after LASIK. I had one patient who was hit directly in the eye three months after LASIK by a tennis ball. She was playing "up at the net" and was struck directly in the eye by a very hard hit tennis ball. The trauma caused a large corneal abrasion, but did not affect the LASIK flap. A corneal abrasion is the same injury I would expect in a non-LASIK eye so, essentially, her LASIK eye was able to withstand significant, direct trauma without affecting the LASIK flap. Her eye healed without complication.