In addition to prisms, vision therapy may also be able to help. You can look at http://www.braininjuries.org for someone who will evaluate and see if vision therapy may be able to help.

The main thing to know is that your medical eye exam may be completely normal and you can STILL have issues with your binocular vision. You need a different type of eye evaluation that will look at how your eyes work together, adjust to near and far, etc. A neuro-ophthalmologist, neuro-optometrist, or behavioral optometrist can help.

Good luck!