It will not cause your eye problems such as blind if you drink mouthwash by accident. You could just drink more water to make the stomach get comfortable. If you feel uncomfortable at the eyes, you could use some eye drops to moisture the eyes. You should not do such mistake next time. You should keep the healthy diet and good rest which will make your body and eyes keep healthy.
No, it isn't.
It won't cause problems or damage to your health unless you drink too much, because mouthwash contains 5x alcohol as much as bud light. If you drink too much, you are behaving like a desperate alcoholic and you may suffer from all the symptoms of alcoholism.
If you drink mouthwash by accident, don't be nervous and just drink more water to attendant it. The main active ingredient in mouthwash is Cetylpyridinium chloride, it will not harmful to your body. So far there we have never heard of drink it will cause eye problem, but if you put it in your eyes by accident, cleaning it by water immediately!