I have trigeminal neuralgia and currently taking carbamezapine , but a couple of days ago now start getting a sharp stabbing pain in my left eye.

Eye pain: The pain may be due to the neuralgia, but you may have a dry eye. Therefore, consult an eye doctor for his opinion.

Clarification: When you get the trigeminal pain does it come n left or right side in which distribution? Also is it related to a particular activity or time? If persists would check back with neurologist.

Trigeminal nerve: Understanding the anatomy and the cause of the trigeminal nerve/neuralgia in your case is useful. If you trigeminal neuralgia is due to ms, an adjacent lesion affecting the v1 portion of the nerve (eye area) is possible.