Uneven pupil dilation is usually a sign of a problem in the efferent nervous pathways. Sometimes injuries or medications can disrupt the pathway, causing uneven pupil dilation.
It can be a sign of a brain tumor, disorders of the optic nerve, brain aneurysm, or can even occur naturally. If you are having this, you should see a neurologist who specializes in eyes.
It is a sign of some sort of head injury whether it is from trauma or from internal damage such as a stroke. Either way it is an emergency someone should get you to the ER as fast as they can. After an event your pupils may not be even again.
The pupils should always dilate equally in the normal state. Any deviation from this is certainly due to a neurological trauma of some kind. A neurologist needs to be consulted.
