- Either over- or under-correction of the problem – While most patients that undergo LASIK report successful results, some may need a second procedure when they do not achieve satisfactory vision after the first. This is more common among patients with higher eye lens prescriptions, and a second surgery cannot be performed until after the eyes have healed from the first surgery, which takes several months. If your eye does not heal from surgery, you may not be able to have an enhancement surgery done.
- The need for corrective lenses even after surgery – Though this is a rare case, some people still need eyeglasses or lenses to achieve perfect vision e.g. due to the normal weakening of vision with age.
- Results of surgery may not be permanent – Some patients of LASIK revert to their previous problems many years after undergoing the surgery. This is uncommon, and mostly occurs in patients that are long-sighted or have hyperopia. If your eyes revert to their original problem, it may be possible to have a second surgery to correct the problem again.
- Visual abnormalities may be experienced– These occur especially in low light conditions, and include:
- Anisometropia i.e. Different refractive powers in the left and right eyes
- Aniseikonia i.e. Different perception of the size of objects in the left and right eyes
- Blurry or hazy vision
- Sensitivity to light
These are rare, but when they occur they may be debilitating and may never heal.
- Persistence or heightening of the symptoms of dry eyes –Most patients report some symptoms of dry eyes after the surgery procedure, and these symptoms wear off, allowing their vision to return to normal. For some patients however, the redness, burning and sometimes reduced vision remain permanently and they need medication to enhance tearing of the eyes to reduce dryness.
Loss of vision – Though a rare occurrence, LASIK may cause a reduction of vision that is beyond the reach of corrective lenses. This could be a result of failure of equipment, damage to the eye or some changes to the shape of the cornea.