Symptoms:

Symptoms may include:

• Double vision when looking to one side (people who are blind in one eye cannot have double vision)
• Headaches
• Pain

Signs and tests:

Tests typically show that one eye has trouble looking to the side, while the other eye moves normally. An examination shows the eyes do not line up -- either at rest, or when looking in the direction of the weak eye.

Your health care provider will do a complete examination to determine the possible effect on other parts of the nervous system. Depending on the suspected cause, you may need:

• Blood tests
• Head imaging study (such as an MRI or CT scan)
• Spinal tap (lumbar puncture)

You may need to be referred to a doctor who specializes in visual problems related to the nervous system (neuro-ophthalmologist).