My 4 week old kittens has opened there eyes and now 2 kittens has one eye each shut and matted I don't know if its infection or if they do this or not please reply with answers to help me get there eyes open and not get infected thanks

It is probably an infection. Try to clean the affected eyes gently with a washcloth dipped in warm water to remove the matted material. You may see pus underneath. If they do not clear up within a day or so, call your vet.