Researchers have found that changes in blood flow in the retina could influence visual symptoms of some migraine patients, a new study has said.

According to the study published in the journal Headache, the findings could represent a long-sought observable marker for migraines that doctors can use to aid in the clinical treatment of the condition.

"While patients with migraines often experience symptoms such as pain around the eye, sensitivity to light, blind spots and visual blurring, the mechanisms behind those symptoms have not been well understood," said the US-based University of California researchers.

The researchers used a non-invasive imaging technique, known as optical coherence tomography angiography, or OCTA, to visualise changes in the retinal blood vessels of migraine patients both during and between migraine attacks.

The imaging was performed on 37 migraine patients with aura symptoms, 30 migraine patients without aura symptoms and 20 healthy patients for a control group, the study noted.

"Researchers found that blood flow decreases in the retina during migraine attacks for both migraine patients with and without aura symptoms. However, patients with aura symptoms were found to have lower blood flow in certain areas of the retina compared to patients without aura symptoms," the study mentioned.

Additionally, asymmetrical blood flow in the retinas was linked to which side of the head migraine patients experienced pain.

The findings could explain why some patients have visual symptoms and could serve as a biomarker for migraine attacks, according to the study.