Migraines and retinal perfusion: A headache for physicians, patients

July 28, 2019

Optical coherence tomography angiography can detect microcirculatory disturbances during acute attacks.

Migraine affects 12% of the population, and is the third most prevalent illness in the world.1 It has been associated with stroke and myocardial infarction, as well as retinal vessel occlusion, ischemic optic neuropathy and normal tension glaucoma, according to Alexander Barash, MD, New York Medical Care.

Speaking at the 2019 American Society of Retina Specialists annual meeting in Chicago, Dr. Barash pointed out that these associations are stronger for those patients who have migraine with aura than without aura.

Whether or not migraine can significantly increase the risk of developing primary open-angle glaucoma remains controversial.2

Aura (which includes visual disturbances and/or other neurologic symptoms) occurs in about 25% of patients who experience migraine,1 and is often a cause for referral to an ophthalmologist.

“During aura, there are changes in the cerebral blood flow,” he said, noting that people who have migraine also have brains that are more easily damaged, and they need a higher blood flow to survive focal ischemia.

Patterns not fully explained
The pattern of migraine aura cannot be fully explained by changes in cerebral blood flow, and the areas of decreased blood flow do not directly correspond to the cortical areas responsible for the aura.

“Aura may indicate more severe ischemia that predisposes to complications,” Dr. Barash said.

Using optical coherence tomography angiography (OCT-A), Dr. Barash and colleagues aimed to identify changes to macular and peripapillary retinal perfusion during migraine with aura.

“We wanted to know-what happens to retinal perfusion during migraine?” he said.

Study Design
Dr. Barash recruited three male patients who had migraine with aura. Patients underwent 3x3 mm and 6x6 mm macular and 4.5x4.5 mm optic nerve head OCT-A scans in both eyes during a baseline day without migraine, and during five episodes of aura and immediate post-aural migraine.

The analysis included angiographic densities of macular superficial and deep capillary layers, and the radial peripapillary capillary layer. (Patients with migraine without aura were not included.)

Study Results
Overall macular perfusion density was significantly decreased during post-aural migraine as compared to that of baseline in the superficial and deep macula 6x6 mm scans (p=4.2 x10^-8 and p=0.03206, respectively), and the deep macula on 3x3 mm (p=0.01996).

The overall perfusion density was significantly decreased during post-aural migraine as compared to that of aura in both the superficial and deep macula on 6x6 mm scans (p=0.00131 and p=0.00689, respectively; see figure).

There were no statistically significant changes to macular perfusion noted between baseline and aura, nor were there significant changes to the peripapillary perfusion between baseline, aura or post-aural migraine.

OCT-A detected microcirculatory disturbances during acute post-aural migraine attacks “may be an important took in elucidating the pathophysiological relationship between migraine, aura, and ischemia,” Dr. Barash said.

“There were acute reductions in retinal perfusion in real time, and this may explain the retinal thinning and progression of glaucoma that you see in patients with migraine," he noted.

Dr. Barash recommended further studies with a greater number of enrolled patients to corroborate his findings.

Question and answer session
During a question and answer session at ASRS, Dr. Barash explained that while he did not account for potential medication use, “it would be interesting to see what the results might be if patients are on vasodilators.”

Dr. Barash also acknowledged that future studies should include females, as migraine tends to affect more women than men (with a lifetime prevalence of 43% for women-about 28 million women in the U.S. alone-and only 18% for men).

The small number of patients in this study did not allow for statistical comparison of concordance between the eyes, but Dr. Barash hopes larger studies will allow for proper powering.

Panelists J. Fernando Arevalo, MD, PhD, FACS, Johns Hopkins University; and Michael S. Ip, MD, Doheny Eye Institute, said they don’t often see patients with migraine. However, while the data was interesting, neither said it would alter current treatments for patients with retinal vein occlusion or glaucoma.
 

References:

1. Migraine Research Foundation. About Migraine. Available at: https://migraineresearchfoundation.org/about-migraine/migraine-facts/
2. Xu C, Li J, Li Z, Mao X. Migraine as a risk factor for primary open angle glaucoma. Medicine (Baltimore). doi: 10.1097/MD.0000000000011377