Retinal migraine is a term used to describe a type of migraine where symptoms affect eyesight. In contrast to other migraines types that affect general eyesight in both eyes, a retinal migraine typically occurs in a single eye. The underlying cause of retinal migraine remains largely unknown. A possible cause discovered upon examining people with active retinal migraine is that some individuals were having a spasm of the blood supply to the retina as their migraine occurred.
How frequently does retinal migraine occur?
While thought to occur only rarely, the true frequency of retinal migraine is really unknown. This may be due to the fact that people who experience this type of migraine might not typically associate their symptoms with a migraine and therefore never make the connection through a formal discussion with their physician. Retinal migraine is most common in women in younger women of childbearing years who have a history of migraine with aura. Generally a diagnosis of retinal migraine is made after other causes are ruled out including other non-migraine related eye disorders.
What are the symptoms of retinal migraine?
- Episodes of fully reversible positive and/or negative visual disturbances within one eye associated with migraine headache.
- Visual changes including flashing rays of light, zigzag lightning patterns or perceptions of bright colored streaks, halos or diagonal lines.
- Visual losses include blurring, blank areas, black dots or spots in the field of vision, causing partial or complete blindness.
- Visual impairment, such as the coming together of spots and “tunnel vision” (not being able to see items in the periphery of one’s visual field), are less common.
- The visual disturbance often occurs on the same side of the migraine headache and may precede, accompany, or rarely, follow it.
How long do the episodes last and is the vision impairment reversible?
- The duration of the visual symptoms may be as short a few seconds but usually lasts many minutes to 1 hour.
- Prolonged but fully reversible visual loss of one eye may rarely occur, sometimes lasting hours, days, or even, weeks.
- Prolonged and permanent visual loss in a single eye appears to occur more commonly in patients with retinal migraine than in cases of simple prolonged typical aura in those with conventional migraine. This makes retinal migraine a potentially more serious condition than migrane with conventional visual aura.
The International Headache Society’s diagnostic criteria for retinal migraine are as follows:
A. At least 2 attacks fulfilling criteria B and C
B. Fully reversible monocular positive and/or negative visual phenomena (eg, scintillations, scotomata or blindness) confirmed by examination during an attack by either or both of the following: (1) Clinical visit field examination (2) The patient’s drawing (made after clear instruction) of a monocular field defect during an attack
C. At least 2 of the following 3 characteristics: (1) The aura spreads gradually over 5 minutes or more (2) Aura symptoms last 5-60 minutes (3) The aura is accompanied, or followed within 60 minutes, by headache
D. Not better accounted for by another ICHD-III diagnosis, and other causes of amaurosis fugal have been excluded
Migraine prevention treatment for retinal migraine?
Although the use of migraine prevention treatment for retinal migraine has not been sufficiently studied, the use of medications to prevent migraine might be warranted according several schools of medical thought. This is due to the fact that people with retinal migraine have a greater chance of permanent vision loss than people with other forms of traditional migraine. Therapy of the acute attack of retinal migraine should probably not include triptans or ergots because of these medications work by constricting blood vessels. Preventative medications that have been tried and have been reported to offer possible benefit include calcium-channelblockers such as verapamil and nifedipine,beta blockers such as metoprolol tricyclic antidepressants such as amitriptyline and some anticonvulsants like topirimate or divalproex . Although no guidelinesare available, low-dose daily aspirin therapy is well tolerated and has been reported anecdotallyto be effective.