Can a fail lasik operation leads to blindness? Is it hurt?

Very little pain. Lasik is not a painful operation. Typically, there is some mild discomfort or feeling of something in your eye for a few hours after the procedure. Usually gone by the next morning. While every operation can have complications, the risk of blindness from lasik is very very small.
LASIK. Lasik is a very safe procedure enjoyed by millions of patients. There are rare risks of serious complications such as infection and perforation of the eye. In more serious cases, blindness is a rare possibility.