What Causes It?
The exact physiology of retinal migraine is not yet known, but researchers believe it may be caused by sudden narrowing (constriction) of blood vessels that reach the eye, reducing blood flow. This restricted flow potentially may be triggered by stress, high blood pressure, smoking, or use of oral contraceptives.
What Are the Symptoms?
The International Classification of Headache Disorders defines the following symptoms of retinal migraine:
- Scintillating scotomas, blind spots that flicker and waver between light and dark
- Partial or total vision loss
- Transient attacks, in which vision defects spread gradually over 5 minutes and last up to an hour
- Headache starting at the same time, or within 60 minutes of, vision disturbances and typically occurring on the same side as vision loss
How Is It Diagnosed?
To diagnose retinal migraine, a doctor may use a screening tool with a light attachment and tiny lenses to observe the retina, optic disc and blood vessels at the back of the affected eye, looking for any damage or reduced blood flow. Because many conditions can restrict blood flow, however, the physician may feel that this testing is best performed during a retinal migraine itself.
The physician may choose to conduct a direct examination with an ophthalmoscope, by indirect examination in which a small probe may be used to apply some pressure to the eye, or via use of a slit lamp and greater magnification of the area under examination.
The doctor may also call for additional diagnostic tests to help eliminate other causes, including computerized tomography (CT scan) or magnetic resonance imaging (MRI scan), or may take blood samples to be analyzed for blood vessel abnormalities, toxins or infections.
How Is It Treated?
During an episode of retinal migraine, it’s advisable to stop activity — particularly in a situation where clear vision is critical, such as driving — and relax until vision returns to normal, preferably in a darkened area that is well ventilated.
To avoid misdiagnosis and possibly permanent damage, it’s important to consult a healthcare professional for any experience of blindness in one eye, however temporary.
Reports suggest that treatment of retinal migraine should be tailored to the patient in the same manner as typical migraine treatment. Some research suggests that the use of propranolol, a beta blocker, should be avoided due to further blood vessel restriction. Most clinicians will also avoid ergots and triptans for retinal migraines, as they also affect blood vessels.
Is It Preventable?
Keeping track of and avoiding certain triggers may help prevent retinal (and other types of) migraine. Depending on the individual, those triggers may include hunger, dehydration, certain foods and additives, lack of sleep, bright lights, or strong odors.