If you find one pupil of your eye slightly larger or smaller than the other, it could be an indication that you are suffering from some disease. Anisocoria is the term used to define such a condition.

If the disorder is an inherited one, then there is nothing to worry. Usually there would be a slight difference in the two pupils of your eyes. But if the difference is more than a millimeter, then there might be something wrong with the body function.

• If the pupil of your eye does not show any dilation under bright or dim light, then you could be suffering from a nerve disorder called Horner’s syndrome.
• Anisocoria could also indicate head injury. It could be a result of Cerebral Aneurysm.
• It might also be as a result of glycoma which can damage the optic nerve severely.
• Severe food poisoning can also result in unequal size of the pupil.
• The difference might arise also due to medication or drug intake.