Double vision usually occurs because the eyes are out of alignment.
Misalignment often is caused by one or more eye muscles that are too short or "tight" because of scar tissue from Graves' ophthalmopathy.
This scar tissue results from changes in the eye because of inflammation.
Prisms might be temporary (pasted on) or permanently ground into your lenses. However, prisms do not work for all people with double vision. Sometimes eye muscle surgery is a more effective treatment.
Eye Muscle Surgery
The goal of eye muscle surgery is to achieve single vision when looking straight ahead and when reading. During eye muscle surgery the muscle is cut from its attachment to the eyeball and reattached further back. Usually eye muscle surgery does not require an overnight stay in the hospital. More than one operation is may be required.