Personally, you needn't take laser eye surgery since you only have slightly nearsightedness. Of course, if you really want to take the surgery, you can do it as long as you are over 18 years old. Except the age limits, you also need take an eye exam so as to know if you have any eye diseases or eye infection. Some people with eye diseases such as pink eyes, dry eyes are not recommend laser eye surgery. Just consult your eye doctor, he/she will told you if you can take the surgery.
Well, I think it is a very personal thing and there may not be dead rules. But I think certain people may not be able to get that surgery. People with dry eyes, an eye infection or some other eye problems had better have thero eyes checked carefull before getting that surgery. By the way, if you are farsighted, you are also not suggested to do that surgery either.