Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: MeganM on 17/02/2020 11:59:23

Title: Why causes ocular migraines, and what are the symptoms of an ocular migraine?
Post by: MeganM on 17/02/2020 11:59:23
Jane has asked:

Why do ocular migraines occur? What causes them, and are they bad for the eyes?

Does anyone have an answer?
Title: Re: Why causes ocular migraines, and what are the symptoms of an ocular migraine?
Post by: chris on 17/02/2020 22:49:53
I've had this happen to me once, about 4 years ago. I remember it well and was intrigued as I watched my own personal fireworks display going off inside one eye for about 10 minutes.

That's the best way I can describe the manifestation: it began around bedtime as colourful, flickering lights centred on one region of my visual field, in just one eye. This pattern slowly spread out like a wave front to involve a wider field of my vision until it had eventually involved my entire retina; I was able literally to watch the progression of the effect as it slowly migrated across my vision. It was painless, began abruptly and without any obvious precipitating cause. It resolved spontaneously within about 10m without any consequences for my vision and no aftermath.

As a doctor, I'd heard about these phenomena, and I recalled learning a bit about them during ophthalmology training,  so I had some sort of inkling about what was happening, but I'd never experienced anything like this before. The neuroscientific geek in me was genuinely fascinated to literally "see" what was obviously a wave of abnormal electrical activity propagating across my retina.

The condition is most often experienced in younger people (under 40) and women; other risk factors include stress, including physiological stress such as hyperthermia, exercise, low blood sugar, and high blood pressure, and some exogenous triggers, like oral contraceptives, smoking and hypoxia (caused by low altitude). Vascular disorders, including arteriosclerosis, lupus, arteritis and occlusive conditions like sickle cell disease have also been linked to retinal migraines.

Apparently the condition occurs owing to a vasospasm (temporary constriction) of the retinal arteries, causing spontaneous electrical discharges in the retina.

It usually resolves spontaneously and without need for any intervention. In rare cases, where the condition is recurrent or disabling, drugs like betablockers and calcium channel blockers can be given to prevent the arterial spasm, and aspirin can be used to reduce the likelihood of thrombus formation. Such treatments are needed very rarely, however.

I certainly found it interesting to watch, but I'm glad it hasn't made a comeback since. It was mildly scary...