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The pathophysiology of the condition is not fully understood, but the timing of some episodic occurrences with the headaches suggests that there is a connection between macropsia and the vasoconstrictive phase of a migraine. [6] The differences in visual phenomena, such as macropsia with slow motion versus macropsia without slow motion, may ...
Scintillating scotoma is a common visual aura that was first described by 19th-century physician Hubert Airy (1838–1903). Originating from the brain, it may precede a migraine headache, but can also occur acephalgically (without headache), also known as visual migraine or migraine aura. [4]
Visual field-bitemporal hemianopia Visual field-binasal hemianopia. A lesion involving complete optic chiasm, which disrupts the axons from the nasal field of both eyes, causes loss of vision of the right half of the right visual field and the left half of the left visual field. [3] This visual field defect is called as bitemporal hemianopia.
The aura of migraine is visual in the vast majority of cases, because dysfunction starts from the visual cortex. The aura is usually followed, after a time varying from minutes to an hour, by the migraine headache. However, the migraine aura can manifest itself in isolation, that is, without being followed by headache.
Illusory palinopsia is a dysfunction of visual perception, resulting from diffuse, persistent alterations in neuronal excitability that affect physiological mechanisms of light or motion perception. Illusory palinopsia is caused by migraines, visual snow, HPPD, prescription drugs, head trauma, or may be idiopathic.
In other clinical sub-forms of migraine headache may be absent and the migraine aura may not take the typical form of the zigzagged fortification spectrum (scintillating scotoma), but manifests with a large variety of focal neurological symptoms. [25] Visual snow does not depend on the effect of psychotropic substances on the brain. [13]
The visual field of each eye can be divided in two vertically, with the outer half being described as temporal, and the inner half being described as nasal. "Bitemporal hemianopsia" can be broken down as follows: bi-: involves both left and right visual fields; temporal: involves the temporal visual field; hemi-: involves half of each visual field
The aura phase of migraine can occur with or without a headache. Ocular or retinal migraines happen in the eye, so only affect the vision in that eye, while visual migraines occur in the brain, so affect the vision in both eyes together. Visual migraines result from cortical spreading depression and are also commonly termed scintillating scotoma.