The result of laser correction does not change over time — it is proven fact. Laser correction underwent multi-stage clinical trials before it was used by ophthalmologists in medical centers and clinics around the world. Laser correction has been widely used since 1985. Long-term observations of patients have shown that the excimer laser does not cause any abnormalities in the eye’s internal structures, as exposure occurs only to one refractive medium, the cornea, and the depth of exposure is strictly limited. There have been no cases of visual impairment or loss due to laser action during the whole period of laser correction.