To meet diagnostic guidelines, attacks must fulfill criteria for migraine with aura and the visual symptoms should be gradual, last 60 minutes or less, and be associated with headache at onset or within 1 hour. The presentation of monocular scotoma, transient monocular total vision loss, or field defects followed by a migraine headache, describes a very rare reversible visual phenomena known as retinal migraine. 6 With such a heterogeneity of described visual symptoms, various tools have been created (eg, the visual aura rating scale ), in attempt to establish a formulary objective approach for guiding a diagnosis. In contrast, occipital lobe seizures are brief and typically present with positive visual phenomena (eg, elemental shapes or well-formed hallucinations), lasting approximately 3 to 5 minutes. By comparison, a monocular visual field deficit, such as a blind spot that is often described as a descending curtain, is a negative symptom that would be more compatible with amaurosis fugax, whereas a sudden onset binocular visual field cut, often with other neurologic deficits, is concerning for cerebral ischemia (Table 2). A gradual-onset disturbance with progression across the visual field, evolution of symptoms from positive to negative, and binocular involvement is more compatible with migraine pathology. Reproduced with permission of the artist.Ĭlassifying visual auras into positive or negative symptoms can help distinguish migraine physiology from other neurologic conditions, notably transient ischemic attacks, strokes, and seizures. Shimmering Rainbow of Pain by Kate Kalmbach. 6 In contrast, a visual field deficit is the most common negative visual aura described. 5 Rarer positive symptoms that have been described include geometric hallucinations, metamorphopsia, micropsia, macropsia, teleopsia mosaic vision, and palinopsia, (Table 1). Some examples of positive symptoms include bright flashing lights, zig-zag lines, colored spots, blurred vision, and scintillations. Positive symptoms typically occur first and are more common. Visual auras can be categorized as positive or negative. Visual auras are subjective and uniquely evolving events thus, their descriptions are variable, with some commonalities across individuals. 4 The diagnostic criteria require at least 2 attacks with 1 or more fully reversible aura symptoms, and at least 3 of the following features: 1) aura spreading gradually over 5 minutes 2) 2 or more auras occurring in succession 3) aura symptoms lasting 5 to 60 minutes 4) unilateral aura 5) positive aura or 6) aura accompanied or followed by a headache within 60 minutes. Migraine with aura is formally defined by the International Classification of Headache Disorders, 3rd edition (ICHD-3) as recurrent attacks of gradual symptoms of reversible visual, sensory, or central nervous system symptoms lasting minutes and followed by headache and migraine symptoms. Visual auras are complex, focal, transient neurologic events involving visual impairments that occur most often before or during the headache phase of a migraine attack and are attributed to a mechanism known as cortical spreading depression (CSD) (see Migraine With Nonvisual Aura in this issue). 3 Considering this high prevalence of visual aura and growing recognition of other visual syndromes associated with migraine, it is prudent for practicing neurologists to recognize the intricate relationship between vision and migraine. 2 Visual auras are most common, occurring in approximately 98% of persons with a diagnosis of migraine with aura. The prevalence of aura is estimated to be up to 33% in people with migraine. Visual disturbances, transient or continuous, are associated with a variety of headache disorders, including migraine with visual aura, retinal migraine, visual snow syndrome (VSS), and Alice in Wonderland syndrome (AWS).
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