How do you get rid of double vision at night?

See ophthalmologist. The cause of your double vision must be determined before it can be treated. A visit to an ophthalmologist is what you need.
Possible cataract. If you are experiencing what you describe as "double vision" only at night, especially when looking at headlights you are more than likely sufferring from "tmb." this stands for "too many birthdays." you are more than likely of an age where you might have aging cataracts in one or both eyes. The reflection of oncoming headlights off of the cataract can result in the symptoms that you describe.

Related Questions

What's the best treatment to get rid of double vision?

Depends. Recent onset doubling of vision can be due to trauma, nerve dysfunction or muscular disorders. The most common of these is damage to the nerves from the brain controlling eye position. You should seek an ophthalmologist or better a neuro-ophthalmologist to sort this out. You may need eye muscle surgery. Prisms and temporary patching for some forms of visual doubling. Read more...
Careful evaluation. Double vision has many causes. If it as a result of misalignment of the eyes, then examination by an ophthalmologist or neurologist is appropriate. Careful investigation is required. Once the cause has been found, and if the diplopia persists, prisms can be incorporated into glasses to correct the double vision. Occasionally sugery is required to reposition the eyeballs. Read more...

How do I get rid of double vision? I have reading /comprehension problems. I am doing the #3-3 cups test, is it healthy with unfocused eyes?

Go see Ophthalmologi. Go see your ophthalmologist (or at least optometrist (no offense intended) to get started if you can't get in to see ophthalmologist). S/he can evaluate & diagnose cause of double vision (diplopia) which is necessary before considering treatment options. Always get diagnosis before talking treatment. Read more...
See an eye doc. There are multiple potential reasons for double vision, some of which can be serious. I would recommend seeing an ophthalmologist for a complete evaluation. Read more...

About a year ago I started having double vision. It really bothers me now, especially when I'm driving or watching a movie. How to get rid of it?

Answer is obvious. If your car was making a funny sound, would you think, "How can I get rid of that funny sound?" or would you think, "I need to take my car in to the mechanic to find out what's making that sound so HE can get rid of the sound"? It's just as true in medicine as in auto repair: First diagnosis, THEN treatment. How can you "get rid" of something when you don't know what is causing that something? Read more...