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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. It is often confused with retinal migraine , which originates in the eyeball or socket.
Retinal migraine is a retinal disease often accompanied by migraine headache and typically affects only one eye. It is caused by ischaemia or vascular spasm in or behind the affected eye.
It is generally classified as an event fulfilling the conditions of migraine with aura with no (or minimal) headache. It is sometimes distinguished from visual-only migraine aura without headache, also called ocular migraine.
The most common auras include motor, somatosensory, visual, and auditory symptoms. [6] The activation in the brain during an aura can spread through multiple regions continuously or discontinuously, on the same side or to both sides. [7] Auras are particularly common in focal seizures.
Sometimes, aura occurs without a subsequent headache. This is known in modern classification as a typical aura without headache, or acephalgic migraine in previous classification, or commonly as a silent migraine.
Migraines and HPPD are probably the most common causes of palinopsia. Idiopathic palinopsia may be analogous to the cerebral state in persistent visual aura with non-migraine headache or persistent visual aura without headache.
When lying down at night and closing the eyes, right before sleep or just before waking up, the complex motion of these patterns can become directly visible without any great effort thanks to hypnagogic hallucination.
Anisometropia causes some people to have mild vision problems, or occasionally more serious symptoms like alternating vision or frequent squinting. However, since most people do not show any clear symptoms, the condition usually is found during a routine eye exam.
A kaleidoscope ( / kəˈlaɪdəskoʊp /) is an optical instrument with two or more reflecting surfaces (or mirrors) tilted to each other at an angle, so that one or more (parts of) objects on one end of these mirrors are shown as a regular symmetrical pattern when viewed from the other end, due to repeated reflection.
Symptoms. Loss of vision. Diagnostic method. Eye examination. Functional visual loss (FVL) also known as Functional vision loss or Nonorganic visual loss (NOVL) is a reduction in visual acuity or loss of visual field that has no physiological or organic basis.