Although there is high success rate, refractive surgeries including LASIK are not perfect. Postoperative visual problems may affect overall correction outcomes. In fact, the way in which the shaped cornea responds to laser energy and the healing process all play their roles in final surgical results. Potential bothersome problems caused by unsatisfied vision correction include blurred or distorted vision, irregular astigmatism, eyestrain and even headaches. In these cases, gas permeable or hybrid contact lenses are needed.

Some people may be diagnosed with refractive errors after an eye exam, which means the eyes can not refract or focus light properly. The eye’s ability to focus light is decisive for one’s vision sharpness. Refractive eyeglasses, contact lenses as well as refractive surgeries can be used to correct a refractive error.