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Non-24-hour sleep–wake disorder causes a person's sleep–wake cycle to move around the clock every day, to a degree dependent on the length of the cycle. This is known as free-running sleep. [citation needed] People with the disorder may have an especially hard time adjusting to changes in "regular" sleep–wake cycles, such as vacations ...
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]
Acephalgic migraine. Acephalgic migraine (also called migraine aura without headache, amigrainous migraine, isolated visual migraine, and optical migraine) is a neurological syndrome. It is a relatively uncommon variant of migraine in which the patient may experience some migraine symptoms such as aura, nausea, photophobia, and hemiparesis, but ...
Optic neuropathy is damage to the optic nerve from any cause. The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain. Damage and death of these nerve cells, or neurons, leads to characteristic features of optic neuropathy. The main symptom is loss of vision, with colors appearing subtly washed out ...
Cluster headache. Cluster headache is a neurological disorder characterized by recurrent severe headaches on one side of the head, typically around the eye (s). [ 1] There is often accompanying eye watering, nasal congestion, or swelling around the eye on the affected side. [ 1] These symptoms typically last 15 minutes to 3 hours. [ 2]
Optic neuritis describes any condition that causes inflammation of the optic nerve; it may be associated with demyelinating diseases, or infectious or inflammatory processes. [ 1] It is also known as optic papillitis (when the head of the optic nerve is involved), neuroretinitis (when there is a combined involvement of the optic disc and ...
Cortical blindness is the total or partial loss of vision in a normal-appearing eye caused by damage to the brain 's occipital cortex. [ 1] Cortical blindness can be acquired or congenital, and may also be transient in certain instances. [ 2] Acquired cortical blindness is most often caused by loss of blood flow to the occipital cortex from ...
Classification of sleep disorders, as developed in the 19th century, used primarily three categories: insomnia, hypersomnia and nightmare. In the 20th century, increasingly in the last half of it, technological discoveries led to rapid advances in the understanding of sleep and recognition of sleep disorders. Major sleep disorders were defined ...