A visual migraine and an ocular migraine are two migraine variants which are sometimes confused for one another.
In brief, ocular migraines are a rare migraine variant, but can be frightening for anyone who suddenly experiences one for the first time. An ocular migraine is when one eye has a temporary loss of vision, or even complete (though temporary) blindness which lasts for between ten and twenty minutes. Ocular migraines can be painless, or they can occur alongside or following a migraine headache.
Visual migraines, on the other hand, are a much more common condition. Visual migraines are sometimes called migraine with aura, and they involve visual disturbances such as flashing lights, wavy lines in the vision, and tunnel vision. These disturbances usually disappear after around thirty minutes, and they affect both eyes. For ocular migraines, the vision loss only occurs in one eye.
To identify whether what is being experienced is an ocular or visual migraine, the sufferer can cover one eye at a time. If the visual disturbance is occurring in only one eye, this should help to make it clear that this is the case.
The causes of ocular and visual migraines are, like all migraines, unclear. We know that migraine headaches have a genetic basis. Added to this, according to the World Health Organisation, migraines seem to be triggered by the activation of a mechanism that, in turn, releases inflammatory substances around nerves and blood vessels in the brain. Certainly, it is the case that imaging studies have shown changes in the blood flow in the brain during ocular migraines and visual auras.
Although harmless (though potentially very scary and painful), if you believe that you are experiencing ocular, visual, or any other variant of migraine, it is important to see your doctor. As well as looking at treatment options, they will want to confirm that your symptoms are not being caused by a serious underlying condition.