During a LASIK operation, a thin superficial layer of cornea is created and temporarily peeled back to allow laser treatment of the underlying tissue. This is called the ‘lasik flap’, and is what provides the quick and painless recovery after LASIK.
Some nerve endings that go into the flap are ‘disconnected’ at the time, and this reduces the feedback that our tear glands get that stimulate tear production. Other factors contributing to dryness also include the change in front corneal curvature and intraoperative disturbances such as exposure and irrigation of the corneal surface.
The nerve endings that were disturbed at the time of LASIK typically regrow within several months, and this usually coincides with disappearance of the dry eye problem. A small percentage of patients have dry eyes out to 6 months after surgery, and among these many will continue improving out to one year or more.
In other words, it is extremely rare to get dry eye that doesn’t recover after LASIK.
Typically dry eyes that take a very long time to recover were already very dry before surgery, and it is often possible to predict the problem so that either the dry eye problem is treated intensively prior to surgery, or the patient may also in severe cases be advised not to have LASIK done.
Also, once the eye has recovered from the drying effects of LASIK, they will return to the pre-existing state of wetness or dryness (that was present before LASIK). As such, an eye that was already dry before LASIK can expect to return to that level of dryness several months after surgery.
