You might think that a migraine is always accompanied by pain, however, some less common types are painless. Although about 20 percent of migraines don't cause noticeable pain, this type of migraine disorder causes symptoms that can potentially interfere with your daily activities.
OCULAR MIGRAINE
The most common type of painless migraine is called an ocular migraine, or "acephalic" migraine. This type of migraine usually causes a visual disturbance, called an aura. Ocular migraines can involve many types of visual changes, including flashing lights, blind spots, double vision and shimmering spots in your visual field. These types of visual phenomena occur without any headache pain.
Abnormal images sometimes move through the visual field and involve bright colors. Occasionally, lights may form into geometric shapes such as stars, which can also move. Symptoms usually develop gradually over 5 to 20 minutes and last for less than 60 minutes.
OTHER SYMPTOMS
Painless migraines sometimes cause more symptoms in addition to visual disturbances. Numbness or tingling may develop in one area of the body and slowly spread. For example, the sensation may begin in the fingers, spread through the hand and arm, cross through the face and pass down the other side of the body.
Mild weakness of the arms and hands might also develop, usually clearing in the same order as it appeared. Rarely, painless migraine may cause spells of amnesia that last an hour or two, transient dizziness or problems speaking.
CAUSES AND RISK FACTORS
Although the exact cause of migraines of any type is not well understood, research suggests that nerves involved with sensation in the head and neck interact abnormally with nearby blood vessels, causing pain in the case of migraine with headache. With painless migraines, abnormal activity of the visual region of the brain -- where signals from your eyes are interpreted -- is probably involved, although this is still under investigation.
Painless migraines are most common in people who have a history of more typical, painful migraine headaches. The risk of ocular migraines increases as you get older, usually occurring first after age 50.
DIAGNOSIS AND TREATMENT
Although the symptoms of a painless migraine understandably cause concern, the condition is generally not serious. However, if you experience symptoms similar to those of a painless migraine, see your doctor or ophthalmologist. It is important to rule out other, potentially serious causes of your symptoms, such as a transient ischemic attack, also known as "mini-stroke."
A vision test called a visual field exam can rule out eye problems that might contribute to visual symptoms. Although painless migraines often require no treatment, discuss possible remedies with your doctor if the episodes interfere with your daily activities.
