Visual snow syndrome

What it is

From: Orphanet

Visual snow syndrome is a rare neurologic disease characterized by persistent continuous bilateral visual experience of flickering snow-like dots throughout the visual field in association with other visual (including palinopsia, enhanced entopic phenomena, nyctalopia, photophobia and photopsia) and non-visual (migraine with or without aura, tinnitus and occasionally tremor) symptoms.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Vitreous floaters · Very frequent (99-80%)

Deposits of various size, shape, consistency, refractive index, and motility within the eye's vitreous humor, which is normally transparent.

Anxiety · Frequent (79-30%)

Intense feelings of nervousness, tension, or panic often arise in response to interpersonal stresses. There is worry about the negative effects of past unpleasant experiences and future negative possibilities. Individuals may feel fearful, apprehensive, or threatened by uncertainty, and they may also have fears of falling apart or losing control.

Bipolar affective disorder · Frequent (79-30%)

Bipolar disorder is an illness of mood characterized by alternating episodes of elevated and depressed moods, which are interspersed with euthymic periods.

Depersonalization · Frequent (79-30%)

A psychological experience or symptom characterized by a sense of detachment or estrangement from oneself or one's surroundings.

Depression · Frequent (79-30%)

Frequently experiencing feelings of being down, miserable, and/or hopeless; struggling to recover from these moods; having a pessimistic outlook on the future; feeling a pervasive sense of shame; having a low self-worth; experiencing thoughts of suicide and engaging in suicidal behavior.

Derealization · Frequent (79-30%)

A subjective experience in which an individual feels a sense of detachment or estrangement from their surroundings, leading to a distorted perception of the external world. It is characterized by a feeling of unreality or unfamiliarity with one's environment, as if things are dreamlike, artificial, or lacking in significance.

Diminished ability to concentrate · Frequent (79-30%)

The inability to focus or concentrate on a specific task, activity, or object. The subject may find themselves unable to grasp or understand written text and re-reads frequently without understanding. Familiar tasks or activities are severely compromised due to the lack of ability to concentrate. Thinking through multi-step problems is typically very difficult or impossible, leading to avoidance of such activities.

Entoptic phenomenon · Frequent (79-30%)

Visual sensations caused by changes within the eye itself, rather than by the normal light stimulation process. Entoptic phenomena are classified in the syndrome as floaters, blue field entoptic phenomenon, photopsia and self-light of the eye.

Fatigue · Frequent (79-30%)

A subjective feeling of tiredness characterized by a lack of energy and motivation.

Irritability · Frequent (79-30%)

An emotional state characterized by negative feelings of heightened frustration, annoyance, or feeling upset, often triggered by internal factors (e.g., fatigue, hunger, unfulfilled desires) or external factors (e.g., social or environmental challenges). Irritability may be unpredictable, and is accompanied by a lowered threshold for emotional reactivity and observable features (speech, facial expressions, or psychomotor activity).

Migraine · Frequent (79-30%)

Migraine is a chronic neurological disorder characterized by episodic attacks of headache and associated symptoms.

Neck pain · Frequent (79-30%)

An unpleasant sensation characterized by physical discomfort (such as pricking, throbbing, or aching) localized to the neck.

Nyctalopia · Frequent (79-30%)

Inability to see well at night or in poor light.

Paresthesia · Frequent (79-30%)

Abnormal sensations such as tingling, pricking, or numbness of the skin with no apparent physical cause.

Other findings in the same source

From: Orphanet

Additional reported features include Photophobia (Frequent (79-30%)); Photopsia (Frequent (79-30%)); Sleep abnormality (Frequent (79-30%)); Tinnitus (Frequent (79-30%)); Tremor (Frequent (79-30%)); Vertigo (Frequent (79-30%)); Brain fog (Occasional (29-5%)); Orthostatic tachycardia (Occasional (29-5%)); Postural instability (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

Inheritance in the source

From: Orphanet

Not applicable

Which doctor should you see?

The suggested department for discussing Visual snow syndrome is Ophthalmology, with a ophthalmologist as the relevant type of clinician. Ophthalmologist; paediatric services for children as appropriate.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which part of the eye or visual pathway is affected?
• What change in vision requires immediate contact with the eye service?
• What are the aims and alternatives of any proposed eye treatment?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Visual snow syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.