Occasionally a patient will not obtain a result as good as expected. If the flap is created well, and the flap appearance the next day is pristine, the likelihood for an excellent result increases dramatically. Even for an experienced ophthalmologist such a flap under a slit lamp microscope may not be visible, or just barely so along the edges of the flap. The effect is much like what you might expect looking down on two disposable soft contact lenses, both wet and one laid on top of the other. If there is no debris between the two lenses, and no folds or wrinkles introduced your view looking straight down will be of a single piece.
Most Lasik flaps heal well and quickly.
Small amounts of debris may get under a Lasik flap without consequence. Micro-irregularities may be introduced that quickly smooth out. Nevertheless, the more pristine the initial appearance, the quicker the vision recovery, and less chance of a rare significant inflammatory reaction or a gross introduction of debris or wrinkling that requires the flap to be lifted a second time or otherwise compromises results. Creating a pristine flap refers to the goal of creating a flap with an interface that is virtually undetectable, as occurs in many cases. With input of many Lasik surgeons the likelihood of creating such a result can be increased, particularly for the novice lasik surgeon.