We might be using the word flap here in differant ways. With LASIK, they remove part of the eye, zap it, and then replace the 'flap' for it to re-attach. When

We might be using the word flap here in differant ways. With LASIK, they remove part of the eye, zap it, and then replace the 'flap' for it to re-attach. When it reattaches, it heals around the edges and this is what causes the HALOs in many people. It can also come loose if you are hit or jarred, like playing sports, boxing, mugged, car accident, pets, etc. With LASEK, they dissolve the protective layer, called the epithelium, zap the eye, and then you keep your eyes closed for 24-48 hours while the epithelium regenerates -- they don't reattach it. With LASEK, there is nothing to come loose later and no edge tissue to cause halos.