Living with migraine involves being aware of other health issues that can be related to migraine. Since this is Glaucoma Awareness Month, I want to touch on the relationship between migraine and normal-tension glaucoma.
Glaucoma is a group of eye diseases that cause damage to the optic nerve. In most forms of glaucoma, the intraocular pressure is higher than normal, which causes damage to the optic nerve. In normal-tension glaucoma, the optic nerve is damaged even though intraocular pressure tests within the normal range.
The damage to the optic nerve that glaucoma causes is not reversible, and glaucoma is the second leading cause of blindness. There are no warning signs of glaucoma, and by the time it has progressed to the point of noticeably affecting vision, severe damage has been done to the optic nerve, severely compromising vision.
When I was in my early 40's, I went to my optometrist for a regular check-up and new contact lenses. As part of the exam, he did a visual field test (pictured above). To do this test, you rest your chin on the device, then look (one eye at a time) into the machine and click a button every time you see a little light. The test is meant to detect defects in the visual field. During that test, a small blind spot was found at the edge of the visual field in my right eye. My optometrist immediately referred me to an ophthalmologist, Dr. Scott Strickler. Dr. Strickler said it looked like normal-tension glaucoma, but that it was rare in people under 60. He referred me to a neuro-ophthalmologist at Ohio State University (OSU) for diagnosis, saying that he wanted to be sure he wasn't missing something, perhaps something neurological. After testing, the neuro-ophthalmologist confirmed the normal-tension glaucoma diagnosis.
The first-line treatment was eye drops to reduce my intraocular pressure, even though mine were within normal range. Although the damage was in only one eye, Dr. Strickler recommended using the drops in both eyes. The eye drops seemed to work for a while, then the visual field test showed glaucoma in my left eye as well as progression in the right. Dr. Strickler sent me to OSU for laser surgery. It didn't help, and the glaucoma progressed. Soon, I'd lost 50 percent of the vision in my right eye and 25 percent in the left. There was actually one bit of good news in all of this. Rather than the glaucoma progressing from the outer edges of the visual field in, creating a tunnel, mine was creating tiny spots throughout the visual field. Instead of losing my peripheral vision, the vision loss in my right eye was like a computer monitor with every other pixel missing. This has left the vision in my right eye seeming as if there's always a shadow across it.
Finally, Dr. Strickler sent me back to OSU for the procedure of last resort - microsurgical trabeculectomy. In this procedure, three sides of a rectangle are cut into the eye, behind the upper eyelid, and the corners tacked. This causes the fluid in the eye to drain through the cut, under the membrane over the eye (sclera). The purpose is to lower the pressure in the eye as far as possible without the eye collapsing. That worked, and there's been no progression in the glaucoma since.
While at OSU, I had some very interesting conversations with the doctors about normal-tension glaucoma and migraine. They were sure that there was a connection. In the general population, 12 percent have migraine. Among their patients with normal-tension glaucoma, 40 percent have migraine. They told me that even though the intraocular pressures had tested normal during exams, intraocular pressure increases during a migraine attack. Their theory was that all of the migraines I'd had over the years had actually caused the glaucoma. They said that could be particularly true in someone my age since I had migraines for so many years before we had abortive treatments such as the triptans.
My reason for sharing all of this with you is that I don't want this to happen to others with migraine. Even though the glaucoma has been stable for several years now, there will always be the chance that it could start progressing again. If it does, there's nothing more that can be done. The last surgery I had was the last-resort treatment, so I live with the fear of becoming totally blind. My lifestyle and independence have also been compromised. My night vision is severely compromised, so I can't drive in the dark. I also can't drive when it's raining or snowing hard because of the darkened conditions.
Remember that there are no early warning signs of glaucoma. I've asked Dr. Strickler about this, and he agrees that everyone with migraine should be screened for normal-tension glaucoma annually with the visual field test. Please consider this and be safe.