One of the most severe side effects of laser eye surgery is the development of debilitating visual symptoms, such as double vision, glares and halos, according to the U.S. Food and Drug administration. Although very rare, these symptoms can persist into a patient's nighttime vision.
Sometimes patients also lose the ability to see during low contrast situations, such as during fog, states the FDA. Their vision during these situations may even be made worse than it was before the patient had the procedure performed. In some cases, a person may experience vision loss entirely, which cannot be repaired or restored.
Another severe side effect of laser eye surgery is called dry eye syndrome, explains the FDA. People who develop this condition cannot produce enough tears to keep their eyes lubricated. As a result, they routinely experience eye discomfort and reduced vision. Other visual symptoms, such as blurry vision, can also happen as a result. In some cases, even with intensive eye drop therapy, the condition may become permanent.
Patients also run the risk of being overtreated or undertreated during the procedure, notes the FDA. Only a certain percentage of patients achieve 20/20 vision without the use of contacts or glasses. Additional treatment may be needed to achieve that level of vision, and it may not be possible.