If the excimer laser removes corneal tissue unevenly, small central islands of tissue may be left in place. These islands may cause visual distortion and may require retreatment. The quality of the laser beam has a lot to do with this issue. Therefore the maintenance of the laser beam is critical to the outcome. They can distort the vision but usually can be removed by lifting the flap and cleaning them off.
All medical treatments carry potential risks.
The excimer laser has over a decade of use globally and the accuracy of the laser is unmatched in comparison to other modalities of treatment. However, rarely complications do occur. They can usually be successfully treated by the refractive surgeon. In PRK, patients often return to work in 3-5 days. There is no discomfort during the procedure.