| Scintillating scotoma | |
|---|---|
| Other names | Visual migraine[1] Teichopsia[2] |
 | |
| Example of a scintillating scotoma, as may be caused bycortical spreading depression | |
| Specialty | Neurology,Neuro-ophthalmology |
| Symptoms | Aura in vision,nausea,dizziness,brain fog |
| Complications | Migraine onset |
| Duration | Less than 60 minutes[3] |
| Causes | Cortical spreading depression |
| Risk factors | Migraine sufferer |
| Differential diagnosis | Persistent aura without infarction,Retinal migraine |
| Prevention | Avoidingmigraine triggers |
| Prognosis | Self-limiting |
Scintillating scotoma is a visualaura that was first described by 19th-century physicianHubert Airy (1838–1903). Originating from the brain, it may precede amigraine headache, but can also occuracephalgically (without headache), also known as visual migraine or migraine aura.[4] It is often confused withretinal migraine, which originates in the eyeball or socket.
Many variations occur, but scintillatingscotoma usually begins as a spot of flickering light near or in the center of the visual field, which prevents vision within the scotoma area. It typically affects both eyes, as it is not a problem specific to one eye.[5][6] The affected area flickers but is not dark. It then gradually expands outward from the initial spot. Vision remains normal beyond the borders of the expanding scotoma(s), with objects melting into the scotoma area background similarly to thephysiological blind spot, which means that objects may be seen better by not looking directly at them in the early stages when the spot is in or near the center. The scotoma area may expand to occupy one half of the visual area of one eye, or it may be bilateral. It may occur as an isolated symptom without headache inacephalgic migraine.[7]
.jpg)
As the scotoma area expands, some people perceive only a bright flickering area that obstructs normal vision, while others describe seeing various patterns. Some describe seeing one or more shimmering arcs of white or colored flashing lights. An arc of light may gradually enlarge, become more obvious, and may take the form of a definitezigzag pattern, sometimes called a fortification spectrum (i.e.teichopsia, from Greek τεῖχος, town wall), because of its resemblance to thefortifications of a castle or fort seen from above.[3] It also can resemble thedazzle camouflage patterns used on ships in World War I. Others describe patterns within the arc as resemblingherringbone orWidmanstätten patterns.[citation needed]
The visual anomaly results from abnormal functioning of portions of theoccipital cortex at the back of the brain, not in the eyes nor any component thereof, such as the retinas.[3] This is a different disease fromretinal migraine, which is monocular (only one eye).[8]
It may be difficult to read and dangerous to drive a vehicle while the scotoma is present. Normal central vision may return several minutes before the scotoma disappears fromperipheral vision.[citation needed]
Sufferers can keep a diary of dates on which the episodes occur to show to their physician, plus a small sketch of the anomaly, which may vary between episodes.[citation needed]
Animated depictions
Scintillating scotomas are most commonly caused bycortical spreading depression, a pattern of changes in the behavior of nerves in the brain during a migraine. Migraines, in turn, may be caused by genetic influences and hormones. People with migraines oftenself-report triggers for migraines involving stress or foods,[9] or bright lights.[10] Whilemonosodium glutamate (MSG) is frequently reported as a dietary trigger,[11] other scientific studies do not support this claim.[12]
TheFramingham Heart Study, published in 1998, surveyed 5,070 people between ages 30 and 62 and found that scintillating scotomas without other symptoms occurred in 1.23% of the group. The study did not find a link between late-life onset scintillating scotoma andstroke.[13]
Symptoms typically appear gradually over 5 to 20 minutes and generally last less than 60 minutes, leading to the headache in classicmigraine with aura, or resolving without consequence inacephalgic migraine.[3] For many sufferers, scintillating scotoma is first experienced as aprodrome to migraine, then without migraine later in life. Typically the scotoma resolves spontaneously within the stated time frame, leaving no subsequent symptoms, though some report fatigue, nausea, and dizziness as sequelae.[14]
British physicianJohn Fothergill described the condition in the 18th century and called itfortification spectrum.[15] The British physicianHubert Airy coined the termscintillating scotoma for it by 1870; he derived it from theLatinscintilla "spark" and theAncient Greekskotos "darkness".[16] Other terms for the condition includeflittering scotoma,fortification figure,fortification of Vauban,geometrical spectrum,herringbone,Norman arch,teichopsia,[17] andteleopsia.[15]
