"a scrambled flickering of form & colour"
Lucien den Arend
A large number of referrals to any eye clinic regard ‘unexplained visual disturbances’. There are several potential causes, including retinal disorders (the principle reason to see an ophthalmologist), but often times the diagnosis ultimately is one of migraine aura. A good history and description from the patient is usually sufficient; though it is reassuring to exclude ocular pathology.
Migrainous aura (‘ocular migraines’), are quite entrancing, as shown above, being mysteriously generated in the brain visual centres of the occipital lobes at the back of the head. They are painless, temporary visual phenomena that seem to follow a repeatable (‘stereotypical’) pattern for any one individual. Usually, the effect is visible in both eyes at the same time - even if it appears just on one side - covering either eye confirms this (‘bilateral simultaneous’) nature. Auras can appear suddenly, creating the sensation of looking through a cracked window with flickering lights (scintillations), shimmering triangular zig-zag lines, flashing lights and patchy visual loss which slowly enlarges and spreads across the field of vision. A patient’s first ever attack can be quite frightening, but ocular migraines are typically harmless and self-resolve without medication within 30 minutes.
Not always are migrainous aura followed by the classical severe, one-sided, prolonged knock-out headache. And not all auras are visual in nature; some include disturbances of hearing, speech, smell, or cause progressive numbness or tingling or generalized weakness.
Ocular migraines usually require no treatment, but understand that safety comes first. If you are driving or performing a visually orientated task, it is important to stop and rest until vision returns to normal.
What causes migraines?
No one is certain. Something upsets the brain, which releases inflammatory substances around the nerves and blood vessels. I personally believe it is a basic human trait, such that anyone can get them - it is just a matter whether you have had yours yet. I have been most intrigued and suspect the basis of migraine is basically the result of a combination of brain fatigue and low blood pressure. I’m not persuaded of the usually mentioned suspected food triggers (chocolate, cheese, red wine), though it is interesting that these may be ingested when tired.
The simple mission is to try and prevent migraines in the first place: I believe it is important to maintain brain energy and normal blood pressure. Get plenty of good sleep, take regular rest breaks, eat and drink on a regular basis.
Do let me know if this works for you! Consider a charitable NHS donation if you wish!