Transcript: Kathleen Digre, MD: The Role of Eye Pain and Photophobia in Migraine, Dry Eyes, and More

Christina Vogt: Hello everyone, and welcome back to another podcast. I’m Christina Vogt, associate editor of the Consultant360 Specialty Network. Today, I’m joined by Dr Kathleen Digre, who is a distinguished professor of neurology and chief of the Division of Headache and Neuro-Ophthalmology at the University of Utah. Thank you for joining me today, Dr Digre.

Dr Digre: Thanks for having me.

Christina Vogt: Today, we will be discussing the diagnosis, management, and treatment of photophobia and eye pain. She recently discussed this topic at the American Headache Society Virtual Annual Scientific Meeting. So first, could you discuss your approach to diagnosing, managing, and treating eye pain and photophobia in your practice, especially in regard to patient medical history and physical exam?

Dr Digre: Yes. Well, this is a problem. Eye pain and photophobia are more common than people realize. In neurology practices, migraine is probably the number one cause of pain, and we found this when we surveyed 2 neurology clinics. And, in an ophthalmology practice, conjunctivitis, blepharitis, and dry eyes were the most common causes of eye pain. And when we surveyed the causes of photophobia, in general, migraine was at the top of the list, followed by dry eyes and also followed by head injury. So, it's really important to realize that this combination of things really go together and are important to recognize the overlap between them.

From a historical point of view, asking questions about underlying migraine in an ophthalmology office would be critical, because many ophthalmologists don't realize that somebody has underlying migraine, and if they have underlying migraine and they have dry eyes, that trigeminal stimulation of the cornea can increase the frequency of people's migraine, and then this can be an important piece of the history.

The other piece I always ask about is head injury, because individuals who've had frequent head injuries or bad head injuries often can have long-standing photophobia. On examination, I'm always looking for signs of central causes–for example, Horner’s Syndrome or afferent pupillary defect–that could go along with something like, let's say, optic neuritis. And, of course, the fundus exam looking for anything like disc swelling. But, most of the time, these individuals come in and they just have really normal examination, and then they have a history that–you have to take the history.

The patients that have eye and photophobia together kind of fall through the cracks, because in an ophthalmology practice, many times ophthalmologists look at the eye and say, “well, the eye exam looks normal.” And, the patient still has eye pain and photophobia. Then they go to a neurologist, and the neurologist who goes, “Well, I'm not sure I know how to treat eye pain and photophobia.” So, I think sometimes neurologists and ophthalmologists may need to partner together to attack this problem, and the things I would really ask the ophthalmologist to do would be to do a careful eye exam, putting a drop of proparacaine into each eye, because those individuals who have decrease in the pain or photophobia from dropping proparacaine probably have dry eye symptoms or some form of corneal irregularity that is causing some of the problem.

Then the next step for the ophthalmologist would be to do a Schirmer’s test, putting a little piece of paper and the lower fornix, and then seeing how far somebody can wet them, and if they have dry eyes, that means less than 10 millimeters of wetting in 5 minutes. Then, they really need to be treated for the dry eye, especially when they have underlying migraine, because as I said, this can actually potentiate the migraine and make it worse. And sometimes, ophthalmologists could do this test, too., and I always say headache specialists should be able to do these tests as well. But, some people are a little bit less comfortable working around the eye, and that's why I say sometimes you need to partner to come up with the right diagnosis.

Christina Vogt: What are some common pitfalls in the treatment of these conditions?

Dr Digre: Well, I think the most common pitfall is lack of recognition that dry eye symptoms may occur in chronic migraine, and ferreting out how much is dry eye and treating that, and then working on treating the migraine–that's the first pitfall.

The second pitfall is not recognizing that there's an anatomic basis for light sensitivity, eye pain coming together, and that comes from the corneal nerves in the cornea, which is part of the first division of 5, which connects to the trigeminal system, which is intimately involved in the migraine process, the trigeminal nucleus caudalis, and the trigeminal system is intimately involved in the migraine process. So, light sensitivity can come from the photo receptor cells or from the melanopsin pathway. That's an intrinsically photosensitive retinal ganglion cell that even blind people, if they're visually blind, can have light sensitivity because of this very ancient cell, phylogenetically ancient cell, that lives in the retina and can transmit into cells within our brain and connect with the pain center and give people photophobia and eye discomfort. So, that's a second pitfall, is not explaining to people when they have that that there's an anatomy behind it.

The third pitfall is that we found that depression and anxiety are higher in individuals that have chronic migraine. And, the importance of that is, even in animal studies, animal studies have even shown us that that laboratory animals–mice, for example–that are blind up to postnatal day 9. When light is shined on them, they make all kinds of noises. And, they're not seeing the light, but they're sensing the light through this melanopsin pathway. And then, it activates their anxiety center and their limbic system. And, in animal studies, we've shown this, and people studies we've shown that this anxiety/depression can be part of this eye pain/photophobia problem. And if you don't recognize this, you don't treat it, it can have deadly consequences.

Christina Vogt: Could you describe a challenging patient case you've seen in your practice?

Dr Digre: I see many challenging patients in my practice. The ones that I think are most challenging are those who come with the chief complaint of eye pain and photophobia. They may have seen 2 or 3 ophthalmologists, 2 or 3 neurologists, and it's just–if you can go through the steps of the examination and history, you could come up with an answer at the end. And, very commonly, migraine is at the basis of the answer, because with migraine, individuals can get what we call central sensitization. That means that if you have irritation coming into the eye, you sensitize that trigeminal nucleus caudalis, and then it sets up a reverberating circuit and causes people to have light sensitivity and eye pain along with their migraine.

Christina Vogt: What research is needed going forward to further advance the treatment of eye pain and photophobia?

Dr Digre: Well, I would love to see more basic scientists get into further understanding how eye pain, photophobia, and migraine are connected. And, there are many people trying to work on this problem, because I think there are a few of us who’ve recognized that this is an underserved area of medicine.

And, the second place I'd like to see more work done is coming up with better treatments. Most of the treatments we have right now are somewhat anecdotal. Headache specialists and neurologists should be at a good spot to help treat a lot of these people, because many times the medications that we use in chronic migraine are some of the same medications that can be used for treating eye pain and photophobia.

Christina Vogt: And then lastly, what key takeaways do you hope to leave with neurologists, ophthalmologists, and related physicians on this topic?

Dr Digre: The first takeaway, I would say, is when you see somebody come into your office with eye pain and photophobia, help make a diagnosis. Get the diagnosis right, and realize that maybe they have underlying migraine, and you're not going to want to treat that if you're an ophthalmologist. Then, partner with a neurologist and then work together, because if they have dry eye symptoms or dry eyes that are contributing to the photophobia and the chronic migraine, you may have to work together on this. And, I really hope people embrace this challenge, because I think that there are a lot of patients that have fallen through the cracks in this area.

The second takeaway is, don't forget to look for depression and anxiety and get that treated as well, because if untreated, depression can lead to death and suicide.

Christina Vogt: Thanks again for joining me today, Dr Digre.

Dr Digre: And thank you so much, Christina, for having me. This has really been fun.

Christina Vogt: For more podcasts like this, visit Consultant360.com.