Before when micro blades were used to cut out flaps, complications were more likely to occur. But now laser is so precise that, complications are rare but they do happen. Even if the complications happen, most of them are minor and easily treatable, talking about major complications like inflammation, this is also treated with steroids. Blindness might be one of major concern to the patient, and yes this does happen to some people, if this happens, cornea transplant may be the last option.