The first point is that there is no link between migraine onset and the wearing or not wearing of glasses. The second point is that there is no link between migraine prevention and/or cessation and the wearing or not wearing of glasses. Migraine is due to anomalous brain activity that cannot be influenced by refractive error or its correction.

I’m going to focus on migraine with aura because in my experience this is what patients with migraine most commonly experience, because I have experience of it and because it may be confused with other forms of aura which have more sinister causes. My experience of migraine with aura is of feeling odd, noticing a small sparkle in the vision of my right eye, watching it brighten and increase in size.

Then, the appearance of a short straight line, another line at an angle to the first and then the slow steady appearance of classic fortifications – reminiscent of the top of a castle wall; photopsia. My first was aged 12 during a geography lesson. It came after a lot of sport but not enough water. I have had four in 30 years.

Always the same sensation and aura, and always after sport and not drinking enough. The fortifications and the sensation of feeling odd last around 30 minutes and then slowly subside in reverse order. No accompanying head ache. I finally learnt the importance of hydration and I drink before, immediately after and where possible during the activity, which results in no migraines.

Self-help literature proposes that people who have migraine with aura develop temporary visual signs which start in the centre of the field of vision and spread outward. These might include:

● Blind spots (scotomas), which are sometimes outlined by simple geometric designs
● Zigzag lines that gradually float across the field of vision
● Shimmering spots or stars
● Changes in vision or vision loss
● Flashes of light.

Some people may also experience other temporary disturbances sometimes such as:

● Numbness, typically felt as tingling in one hand or on one side of the face that may spread slowly along a limb,
● Speech or language difficulty,
● Muscle weakness.

The cause of migraine with aura is not clear. Migraine with visual aura may be caused by an electrical or chemical wave that moves across that part of the brain that processes visual signals resulting in visual hallucinations. Many of the same factors that trigger migraine can also trigger migraine with aura, including stress, bright lights, some foods and medications, too much or too little sleep, and menstruation.

Risk factors

There are other eye and pathway diseases that can cause photopsia. Partial posterior vitreous detachment can pull on the retina and cause flashes of light in the vision of the affected eye. The liquefied vitreous may also slosh around the ocular cavity and cause flashes when it impacts the retina. A detached retina is mobile and as it moves flashes may be noticed.

There are other conditions which can cause photopsia:

– Age-related macular degeneration
– Vertebrobasilar insufficiency
– Optic neuritis
– Occipital lobe infarction (similar to occipital stroke).

In EyeTools Journal #17 I wrote about three cases of choroidal melanoma where there was a symptom of flashing lights and in EyeTools Journal #26 I described the photopsia symptom being experienced by a patient with a brain tumour.

Watch out for these. Migraine with aura is debilitating but it can be treated and has a good prognosis.

Don’t confuse it with flashes due to posterior vitreous/retinal detachment or those associated with brain or pathway tumours or choroidal melanoma.