This study is more technical than most we write about on the TheraSpecs blog, but it’s interesting insight into migraine and dry eye, both of which can cause photophobia. We'll cover the migraine aspect today; our next post will address the study's findings related to dry eye.

The trigeminovascular network (also called the trigeminal system) is thought to play a crucial role in migraine. The primary sensors of this network include nerve fibers that carry messages. Abnormality in these nerve fibers might contribute to eye pain in people with migraine.

Changes in the cornea could trigger migraine attacks or add to the many symptoms of migraine, including a feeling of dry eyes. People with both migraine and dry eye syndrome are at particular risk because dry eye itself could trip the trigeminal network.

This study compared the structure of the nerves in the corneas of people with chronic migraine to those in people without migraine. The participants include 19 people with chronic migraine and 30 people without migraine.

Participants with chronic migraine had a reduced density of the nerve fibers in their corneas. These changes, according to the researchers, back up the belief that the trigeminal system plays a role in migraine. This finding also led researchers to think that the structural changes could either cause or be caused by migraine.

Researchers also looked at whether the participants with chronic migraine had symptoms of dry eye syndrome. We'll cover that part of the study in our next post.

REFERENCE

Kinard, K. I., Smith, A. G., Singleton, J. R., Lessard, M. K., Katz, B. J., Warner, J. E., Crum, A. V., Mifflin, M. D., Brennan, K. C. & Digre, K. B. (2015). Chronic Migraine Is Associated With Reduced Corneal Nerve Fiber Density and Symptoms of Dry Eye. Headache: The Journal of Head and Face Pain.