Double vision, otherwise called diplopia, generally results from either a misalignment of your eyes or a structural problem with the part or parts of the eye that let light into it. There are two types of double vision. The first type is called binocular. The second type is referred to as monocular.

Monocular diplopia is differentiated from binocular diplopia by a simple test. If the double vision stops when you cover one eye, then you are suffering from binocular diplopia.  If the double vision persists even with one eye covered, that means you are experiencing monocular diplopia.

There are many different causes for diplopia. The problem can arise from the eyes themselves, the surrounding orbit, or the central nervous system. Causes of double vision include corneal infections or scars, cataracts, eye muscle weakness from thyroid problems, nerve damage from diabetes or multiple sclerosis, autoimmune disease such as myasthenia gravis, brain tumors or aneurysms, strokes, head trauma, orbital trauma, direct eye trauma and even migraine headaches.

Double vision can occur by itself with no other symptoms. Depending on the cause other symptoms may be present with diplopia:

• Droopy eyelids
• Pain with eye movements
• Headache
• Nausea
• Misalignment of one or both eyes (a "wandering eye" or "cross-eyed" appearance)
• Weakness of the eye(s) muscles or other muscles

Double vision that's new or unexplained requires urgent medical attention. With so many potentially serious causes for diplopia, it's important to discover the reason without delay. A thorough history and physical examination are critical to localizing a disease process and guiding further tests and studies to identify and treat the cause.

If you or someone you know suffers from double vision, it is important that they schedule an appointment for an examination by calling Eyecare Medical Group at 207.828.2020.