Closed-eye hallucinations and closed-eye visualizations ( CEV ) are hallucinations that occur when one's eyes are closed or when one is in a darkened room. They should not be confused with phosphenes , perceived light and shapes when pressure is applied to the eye's retina, or some other non-visual external cause stimulates the eye. Some people report CEV under the influence of psychedelics ; these are reportedly of a different nature than the "open-eye" hallucinations of the same compounds. Similar hallucinations that occur due to loss of vision are called " visual release hallucinations ".
33-455: CEV may stand for: Medical [ edit ] Closed-eye visualization , a class of hallucination Clinically extremely vulnerable , an NHS category for those at high risk from a COVID-19 infection Religion [ edit ] Contemporary English Version , a translation of the Bible into English 1995 Venezuelan Episcopal Conference ,
66-556: A neurological disorder , where a person experiences constant visual disturbances, regardless of lighting conditions. Visual snow syndrome is often linked to heightened neural sensitivity in the visual system and may require diagnosis and treatment, as it could be associated with underlying eye conditions or neurological disorders. In summary: In addition to visual snow, many of those affected have other types of visual disturbances such as starbursts, increased afterimages , floaters , trails, and many others. Visual snow likely represents
99-476: A Venezuelan Catholic archdiocesan organization Vehicles [ edit ] Crew Exploration Vehicle , NASA's proposed human spaceflight system, now known as Orion Combat engineering vehicle , armoured vehicles supporting battlefield engineering works M728 combat engineer vehicle , a combat engineer vehicle mounted on a tank chassis Other [ edit ] European Volleyball Confederation (French: Confédération européenne de volleyball),
132-402: A bit of relaxation and concentration to achieve. When properly relaxed, it is possible to cause regions of intense black, bright white or even colors such as yellow, green, or pink to appear in the noise. These regions can span the entire visual field, but seem to be fleeting in nature. This level is relatively easily accessible to people who use psychedelic drugs such as LSD . However, it
165-639: A clinical continuum, with different degrees of severity. The presence of comorbidities such as migraine and tinnitus is associated with a more severe presentation of visual symptoms. Non-visual symptoms may include difficulty concentrating, insomnia, frequent migraines, nausea, and vertigo. Visual snow syndrome is usually diagnosed with the following proposed criteria: Additional and non-visual symptoms like tinnitus , ear pressure, brain fog , and more might be present. It can also be diagnosed by PET scan . Migraine and migraine with aura are common comorbidities . However, comorbid migraine worsens some of
198-480: A pricing model Equivalent carbon content , also called "carbon equivalent value", a property of alloy steels Centre d'essais en vol , a flight testing centre in Brétigny-sur-Orge, France European Volunteer Centre Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title CEV . If an internal link led you here, you may wish to change
231-424: A random field of lightness or darkness that overlays the redness or blackness of closed eyelids. For a person who tries to actively observe this closed-eye perception on a regular basis, there comes a point where if they look at a flat-shaded object with their eyes wide open, and try to actively look for this visual noise, they will become aware of it and see the random pointillistic disorganized motion as if it were
264-637: A translucent overlay on top of what is actually being seen by their open eyes. When seen overlaid onto the physical world, this CEV noise does not obscure physical vision at all, and in fact is hard to notice if the visual field is highly patterned, complex, or in motion. When active observation is stopped, it is not obvious or noticeable, and seemingly disappears from normal physical perception. Individuals suffering from visual snow syndrome see similar noise but experience difficulty blocking it from conscious perception. Some mental control can be exerted over these closed-eye visualizations, but it usually requires
297-402: Is a normal reaction of the body, related to the way photoreceptors (rods) and neurons respond to weak or insufficient stimuli. However, if visual snow becomes persistent and continuous — especially if it is accompanied by other symptoms, such as headaches, difficulty focusing, or intense visual distortions — it may indicate visual snow syndrome . This syndrome is not just a phenomenon, but
330-473: Is also accessible to people involved in deep concentration for long periods of time. 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 . The patterns themselves might resemble fractals . This is a fairly deep state. At this level, thoughts visually manifest as objects or environments. When this level
363-503: Is inhibited during REM sleep, and the imagination can freely run into the perceptual systems. What happens at level 5 is likely that this system is inhibited, just like in REM sleep, by different causes like sensory deprivation, psychedelic drugs or meditative relaxation techniques. Image burn-in occurs when very bright objects lie in one's field of vision, and should not be confused with closed-eye hallucinations. Visual burn-in from bright lights
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#1732851479096396-495: Is reached, the CEV noise seems to calm down and fade away, leaving behind an intense flat ordered blackness. The visual field becomes a sort of active space. A side component of this is the ability to feel motion when the eyes are closed. Opening the eyes returns one to the normal physical world, but still with the CEV object field overlaid onto it and present. In this state, it is possible to see things that appear to be physical objects in
429-429: Is still normal to experience level 3, and even level 4; however, only a small percentage of the population does this without psychedelic drugs, meditation or extensive visualization training. The most basic form of CEV perception that can be immediately experienced in normal waking consciousness involves a seemingly random noise of pointillistic light or dark regions with no apparent shape or order. This can be seen when
462-454: Is typically always present and has no known cure, as viable treatments are still under research. Astigmatism , although not presumed connected to these visual disturbances, is a common comorbidity. Migraines and tinnitus are common comorbidities that are both associated with a more severe presentation of the syndrome. The cause of the syndrome is unclear. The underlying mechanism is believed to involve excessive excitability of neurons in
495-415: Is unrelated to the visual noise seen when the retina is physically stimulated. The retina can be made to produce light patterns of visual noise simply by one rubbing their eyes somewhat forcefully in a manner that increases intraocular pressure. Additionally, retinal noise can be produced by touching near the rear of the eyeball producing pressure phosphenes (for example, if one closes one's eyes, looks all
528-419: Is visible for a few minutes after closing the eyes, or by blinking repeatedly, but the burn-in effect slowly fades away as the retina recovers, whereas the waking-consciousness CEV noise will not disappear if observed continuously over a period of time. CEV does not include entoptic phenomena such as " floaters ", which are instead caused by opacities in the vitreous humour and often appear as cells or strands in
561-422: The "sprites" ( blue field entoptic phenomenon ) that can be seen as dots darting around when staring up into a bright blue sky on a sunny day (not looking at the sun). These dots superimposed over a flat blue background are white blood cells moving through the blood vessels of the retina. The motion of waking-consciousness CEV noise is uniformly random compared to the waking-consciousness blue-sky sprite motion. CEV
594-490: The additional visual symptoms and tinnitus seen in "visual snow" syndrome. This might bias research studies by patients with migraine being more likely to offer study participation than those without migraine due to having more severe symptoms. In contrast to migraine, comorbidity of typical migraine aura does not appear to worsen symptoms. Psychological side effects of visual snow can include depersonalization , derealization , depression , photophobia , and heliophobia in
627-557: The cone signals are dominated by intrinsic noise". The causes of VSS are not clear. The underlying mechanism is believed to involve excessive excitability of neurons within the cortex of the brain , specifically the right lingual gyrus and left cerebellar anterior lobe of the brain. Persisting visual snow can feature as a leading addition to a migraine complication called persistent aura without infarction , commonly referred to as persistent migraine aura (PMA). In other clinical sub-forms of migraine headache may be absent and
660-401: The connection of visual snow to HPPD and the cause and prevalence of HPPD are disputed. Most of the evidence for both is generally anecdotal and subject to spotlight fallacy . Visual snow has also been correlated with head trauma and infection. It is difficult to resolve visual snow with treatment, but it is possible to reduce symptoms and improve quality of life through treatment, both of
693-487: The continental European volleyball governing body Certified Video Engineer , a professional title regulated by the Society of Broadcast Engineers Chemins de fer électriques Veveysans , a Swiss railway company Cochrane Eyes and Vision , a collaboration of researchers and healthcare professionals Coherent Extrapolated Volition , an approach to friendly artificial intelligence Constant elasticity of variance model ,
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#1732851479096726-459: The eyes are closed and looking at the back of the eyelids. In a bright room, a dark red can be seen, owing to a small amount of light penetrating the eyelids and taking on the color of the blood it has passed through. In a dark room, blackness can be seen or the object can be more colourful. In either case, it is not a flat unchanging redness/blackness. Instead, if actively observed for a few minutes, one becomes aware of an apparent disorganized motion,
759-411: The field of vision. Full-closing and reopening the eyelids creates a very definite wiper-ridge in the tear film that is readily visible. Fully closing and reopening the eyelids also often stirs up the vitreous which settles down after a brief moment due to gravity. The motion of waking-consciousness CEV noise is not so directly and physically controllable and repeatable. CEV does not seem to be related to
792-434: The individual affected. Patients with visual "snow" have normal equivalent input noise levels and contrast sensitivity . In a 2010 study, Raghaven et al. hypothesize that what the patients see as "snow" is eigengrau . This would also explain why many report more visual snow in low light conditions: "The intrinsic dark noise of primate cones is equivalent to ~4000 absorbed photons per second at mean light levels; below this
825-458: The latter is an unreal perception in the absence of stimuli. Visual snow syndrome Visual snow syndrome ( VSS ) is an uncommon neurological condition in which the primary symptom is that affected individuals see persistent flickering white, black, transparent, or colored dots across the whole visual field . Other common symptoms are palinopsia , enhanced entoptic phenomena , photophobia , and tension headaches . The condition
858-463: The limited size of any studied cohort, though the issue of diagnosis is now largely addressed. Initial functional brain imaging research suggests visual snow is a brain disorder . Visual snow is a phenomenon where a person perceives visual disturbances, such as fine graininess or "static," in their field of vision. This can occur in low-light conditions, in the dark, or when the visual system amplifies light perception. In these cases, visual snow
891-580: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=CEV&oldid=1190984963 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Closed-eye visualization There are five known levels of CEV perception which can be achieved either through chemical stimuli or through meditative relaxation techniques . Level 1 and 2 are very common and often happen every day. It
924-415: 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. Visual snow does not depend on the effect of psychotropic substances on the brain. Hallucinogen persisting perception disorder (HPPD), a condition caused by hallucinogenic drug use, is sometimes linked to visual snow, but both
957-409: The open-eye physical world, but that aren't really there. If we remember that the essential difference between what we call the real world and the world of imagination and hallucination, is not the elements of which we build them up but the sequence in which these elements appear... then it follows that the sequences directed from without represent a limitation of the otherwise unlimited combinations of
990-505: The right lingual gyrus and left anterior lobe of the cerebellum . Another hypothesis proposes that visual snow syndrome could be a type of thalamocortical dysrhythmia and may involve the thalamic reticular nucleus (TRN). A failure of inhibitory action from the TRN to the thalamus may be the underlying cause for the inability to suppress excitatory sensory information. Research has been limited due to issues of case identification, diagnosis, and
1023-545: The selective forms released at random from within. This level can be entered from complete sensory deprivation, as experienced in an isolation tank or deep trance of hypnosis , but even there it requires great relaxation. According to lucid dreaming researcher Stephen LaBerge , perceptions can come from either the senses or imagination. An inhibitory system involving the thalamus , likely involving serotonergic neurons , inhibits imaginary perceptions from becoming too activated so they turn into hallucinations. This system
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1056-556: The syndrome and its comorbidities. In some studies, lamotrigine as a treatment for visual snow syndrome only showed efficacy in 20% of patients, and in one study, patients using lamotrigine even reported worsening symptoms. Medications that may be used include lamotrigine , acetazolamide , verapamil , clonazepam , propranolol , and sertraline but these do not always result in positive effects. As of 2021, two ongoing clinical trials were using transcranial magnetic stimulation and neurofeedback for visual snow. A recent study in
1089-430: The way left, and lightly touches the rightmost part of the eye socket, this produces visual noise in the shape of a circle that appears at the left side of the visual field – a practice that is neither painful nor dangerous). None of these are closed-eye hallucinations, but rather the experience of mechanical stimuli distorted into visual stimuli. Thus, pressure phosphenes are sensory distortions, and not hallucinations, as
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