What Are Ocular Migraines?
The first time you have an ocular migraine, it may fill you with fear. During an ocular migraine, you will experience a decrease in vision or even complete blindness for a short period of time. Symptoms may vary between individuals, but there are several common symptoms related to ocular migraines.
Retinal migraines generally involve only one eye. Many people assume that retinal migraines are the only type of ocular migraine or use the term ocular migraine to describe a retinal migraine. Retinal migraines may occur due to a temporary constriction of blood vessels in one eye for a period of time.
A small, slowly growing blind spot in your central vision. Unlike traditional migraines, when vision might start to decrease at the edges or “tunnel” as it progresses, ocular migraines begin in your central vision: right in front of your eye. Initially, the spot, known as a scotoma, may be relatively small. As the migraine increases, however, it may grow or lead to complete blindness in the affected eye.
Bright, flickering lights within the blind spot. While you may be unable to see what’s going on around you, you may experience bright, flickering lights within the blind spot in your vision.
Shimmering, zig-zag lines within the blind spot. Instead of bright, flickering lights, some people experience zig-zag lines traveling across the blind spot.
The blind spot moves across your field of vision. In some cases, the blind spot may not grow to encompass your entire visual field in one eye. Instead, it may move from one point to another or shift slowly across your field of vision until it eventually dissipates.
Full Ocular Migraines
Unlike retinal migraines, full ocular migraines often occur in both eyes. You may experience full blindness, including both a gradual decrease of vision or a sudden onset of blindness in both eyes. You may have flashing lights, zig-zags, or floaters within your field of vision while remaining unable to see what’s going on around you.
You may struggle to tell whether migraine symptoms occur in one eye or in both eyes. Sometimes, visual disturbance may appear to be localized to one area of your field of vision, but you may find it spreads further than you think. Other times, it may seem to spread fully across your field of vision but be isolated to one eye. Covering one eye then the other will allow you to better determine whether an ocular migraine is limited to one eye or spreads across both eyes.
Are Ocular Migraines Harmful?
In general, ocular migraines are not considered harmful. Most people have no symptoms other than blindness or blind spots. Neither retinal migraines nor full ocular migraines are, in and of themselves, harmful. However, in some cases, retinal or ocular migraines may be a sign of a more serious problem. If you have a retinal or ocular migraine, it’s important to consult with a doctor as soon as possible to undergo an evaluation and ensure your symptoms don’t signal a larger problem.
Most of the time, ocular migraines are not caused by actual visual symptoms nor is their trigger within the eye. Instead, they are caused by migraine activity within the visual cortex of the brain.