Changes in retinal vessel diameters in migraine patients during attack-free period

Using optical coherence tomography and optical coherence tomography angiography to delineate neurovascular homeostasis in migraine: a review

Migraine is one of the world's most debilitating disorders, and it has recently been shown that changes in the retina can be a potential biomarker for the disease. These changes can be detected by optical coherence tomography (OCT), which measures retinal thickness, and optical coherence tomography angiography (OCTA), which measures vessel density. We searched the databases Google Scholar, ProQuest, Scopus, and Web of Science for studies in English using OCT and OCTA in migraineurs, using the search terms "optical coherence tomography," "OCT," "optical coherence tomography angiography," "OCTA" and "migraine." We found 73 primary studies, 11 reviews, and 8 meta-analyses pertaining to OCT and OCTA findings in migraineurs. They showed that migraineurs had reduced retinal thickness (via OCT), retinal vessel density, and greater foveal avascular zone area (via OCTA) than controls. OCTA changes reflect a perfusion compromise occurring in migraineurs as opposed to in healthy controls. OCT and OCTA deficits were worse in migraine-with-aura and chronic migraine than in migraine-without-aura and episodic migraine. Certain areas of the eye, such as the fovea, may be more vulnerable to these perfusion changes than other parts. Direct comparison between study findings is difficult because of the heterogeneity between the studies in terms of both methodology and analysis. Moreover, as almost all case-control studies were cross-sectional, more longitudinal cohort studies are needed to determine cause and effect between migraine pathophysiology and OCT/OCTA findings. Current evidence suggests both OCT and OCTA may serve as retinal markers for migraineurs, and further research in this field will hopefully enable us to better understand the vascular changes associated with migraine, perhaps also providing a new diagnostic and therapeutic biomarker.

Retinal microvasculature features in patients with migraine: a systematic review and meta-analysis

Background

Migraine is a central nervous system disorder involving neuronal and vascular factors. The brain has a close anatomical relationship with retinal vessels and similar regulatory processes, and the retinal vascular system is the only in vivo vessel that can be directly visualized, while optical coherence tomography angiography (OCTA) is an advanced retinal vascular imaging technique. In this study, OCTA was used to study the retinal vascular density (VD) and foveal avascular zone (FAZ) in migraine patients, which provided a theoretical basis for its use as a candidate for rapid and non-invasive diagnosis of migraine.

Methods

Published studies comparing retinal microvascular profiles between migraine patients and healthy controls were obtained by a comprehensive search of electronic databases. Nine studies were finally included, including 775 eyes (migraine group: 444 eyes, control group: 331 eyes). Pooled effect sizes were presented as standardized mean differences (SMDs) and 95% confidence intervals (CIs). Statistical analysis was performed using Review Manager software (version 5.30).

Results

The combined results revealed that the superficial and deep macular whole enface VD (MWEVD) (superficial VD: SMD = -0.30, P = 0.0001; deep VD: SMD = -0.61, P = 0.02), superficial foveal VD (FVD) (SMD = -0.42, P = 0.03), deep parafoveal VD (PFVD) (SMD = -0.31, P = 0.002), and peripapillary VD (PVD) (SMD = -0.49, P = 0.002) were significantly reduced in migraine patients compared with healthy people. However, there was a significant increase in the area of the FAZ in migraine patients (SMD = 0.56, P < 0.0001).

Conclusion

Migraine patients are prone to retinal microcirculation disorders, such as decreased blood vessel density and increased avascular area in the fovea. This provides a theoretical basis for OCTA as a candidate for rapid, non-invasive diagnosis of migraine.

L-arginine and aged garlic extract for the prevention of migraine: a study protocol for a randomised, double-blind, placebo-controlled, phase-II trial (LARGE trial)

Background

Migraine is a common and distressing neurological condition characterised by recurrent throbbing headaches, nausea and heightened sensitivity to light and sound. Accumulating evidence suggests that cerebral arteries dilate during migraine, causing distal microvessels to constrict, which could activate nociceptors and cause onset of headache pain. If so, preventing or attenuating chronic microvascular constriction, and promoting a dilatory phenotype, may reduce frequency and/or severity of migraines. The primary aim of the L-Arginine and Aged Garlic Extract (LARGE) trial is to investigate whether oral treatment with dietary nutraceuticals, L-arginine and aged garlic extract (AGE), both systemic vasodilatory agents, will alleviate migraine frequency, duration and severity in adults with chronic frequent episodic migraines.

Methods

The study is a randomised double-blind placebo-controlled phase-II single-site clinical trial conducted in Perth, Australia. The target sample is to recruit 240 participants diagnosed with chronic frequent episodic migraines between 18 and 80 years of age. Participants will be randomised to one of four treatment groups for 14 weeks (placebo induction for 2 weeks, followed by 12 weeks on one of the respective treatment arms): placebo, L-arginine, AGE, or a combination of L-arginine and AGE. The doses of L-arginine and AGE are 1.5 g and 1 g daily, respectively. The primary outcome is to assess migraine response using change in migraine frequency and intensity between baseline and 12 weeks. Secondary outcomes include the impact of L-arginine and/or AGE on photosensitivity, retinal vessel changes, and blood biomarker concentrations of vascular tone, following a 12-week intervention.

Discussion

The protocol describes the oral administration of 2 nutraceutical-based interventions as possible prophylactic treatments for chronic frequent episodic migraines, with potential for direct clinical translation of outcomes. Potential limitations of the study include the fixed-dose design of each treatment arm and that in vivo neuroimaging methods, such as magnetic resonance imaging (MRI), will not be conducted to determine putative cerebro-vasodilatory changes to coincide with the outcome measures. Dose-response studies may be indicated.

Trial registration

The trial was retrospectively registered with the Australian New Zealand Clinical Trials Registry ACTRN12621001476820 (Universal Trial Number: U1111-1268-1117) on 04/08/2021. This is protocol version 1, submitted on 25/11/2022.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-023-03149-y.

Are Retinal and Peripapillary Blood Flows Affected during Migraine Attack?

Migraine pathophysiology is complex and partially includes the vasculature. This study compared retinal and peripapillary blood flow parameters in migraine patients during an attack with healthy controls using optical coherence tomography angiography (OCTA). A prospective clinical study was conducted including 52 eyes from 26 migraineurs and 48 eyes from 24 healthy controls. OCTAs were performed with RTVue XR Avanti using AngioVue software. OCTA imaging was performed during the attack period in migraineurs before any treatment for the attack. Vascular densities in the whole image, fovea, superior hemisphere, inferior hemisphere, and temporal, superior, nasal, and inferior regions of the parafoveal area and in the superficial and deep capillary plexuses were acquired and statistically analysed. The flow density parameters were measured in the superficial retinal capillary plexus, deep retinal capillary plexus, outer retinal capillary plexus, and choriocapillaris layers of the macula in a 3-mm diameter area. The peripapillary flow densities were measured for the optic nerve head, vitreous, radial peripapillary capillaries, and choroid in a 4.50-mm diameter area around the optic disc. Vascular density measurements in the superficial plexus were similar between migraineurs and controls (p > .05). Vascular densities in the deep capillary plexus were similar between groups (p > .05), except in the deep superior area (p = .05). Flow areas in the nerve head, vitreous, peripapillary capillary, and choroid segments were similar between migraineurs and controls (p > .05). Macular thickness parameters were also similar between groups (p > .05). The results suggest that an acute migraine attack does not affect retinal or peripapillary blood flow.

Association of Meniere's disease and retinal vascular calibre: a prospective observational study in China

OBJECTIVE

It is believed that Meniere's disease (MD) is associated with vascular disorders, but few studies have reported the relationship between retinal vascular disorders and MD. We evaluated and compared the retinal vascular calibres in patients with MD with healthy subjects matched for age, sex and vascular risk factors using retinal photographs to explore the association between MD and retinal vascular calibre.

STUDY DESIGN

A prospective study.

SETTING

Tertiary referral centre.

PARTICIPANTS

Sixty patients with MD and 62 healthy subjects matched for age, sex and vascular risk factors were enrolled in this study. Twenty-four patients with MD had migraines, and 36 patients with MD did not have migraines.

MAIN OUTCOME MEASURE

Retinal vascular calibres were calculated and compared not only between patients with MD and healthy subjects but also between subgroups of patients with MD.

RESULTS

Compared with healthy subjects, patients with MD had a slightly larger retinal artery calibre (126.30±10.45vs 119.61±15.86, p=0.006) and a higher retinal artery/vein ratio (0.79±0.09vs 0.75±0.10, p=0.005). Among patients with MD, those with migraines had a larger retinal artery calibre (130.73±11.55vs 123.35±8.61, p=0.006) than those without migraines. Moreover, the presence of migraines and the high frequency of vertigo attacks appeared to increase the retinal artery calibre.

CONCLUSIONS

Our study suggests that a relationship exists between retinal vascular calibre and MD. Although the pathophysiological relationship between migraine and MD remains unclear, the presence of migraine attacks may aggravate endolymphatic hydrops (EH) and accelerate the outflow of EH in patients with MD. More extensive studies are required to explore the association between retinal vascular calibre and MD.