Hallucinations are regarded by mental health professionals as sensory experiences that may seem real, but are actually created in your mind. Visual hallucinations, for example, cause you to see images, people, and objects that you alone may see.

But it’s also possible to have visual hallucinations with your eyes closed. Seeing patterns, lights, and colors when you shut your eyes is a natural phenomenon called closed eye hallucinations. Some causes, however, may be related to underlying medical conditions.

Read on to learn the different items you may possibly “see” with your eyes closed, and how to tell whether these are causes for concern.

When you close your eyes, you may be able to “see” colors, shapes, and light. Some of the images may also move or create a swirling effect. Such visual effects are sometimes called closed eye hallucinations because such objects aren’t literally in front of you.

In contrast to eye-open hallucinations, the visual phenomena you see when you shut your eyes often have kaleidoscope effects. This is especially the case if you’re awake and in a lit-up space while your eyes are closed.

Some of the most common types of closed-eye hallucinations include:

  • swirling patterns and colors
  • random pixels
  • flashes of light and/or darkness
  • random objects

If you’re sleeping and you see clearer images of people, objects, and places, these are more likely to be dreams than hallucinations. However, some dreams can indeed seem very real from time to time.

Closed-eye hallucinations are related to a scientific process called phosphenes. These occur as a result of the constant activity between neurons in the brain and your vision.

Even when your eyes are closed, you can experience phosphenes. At rest, your retina still continues to produce these electrical charges.

If you close your eyes in a lit-up room or outside in the sunlight, chances are that small amounts of light could create a visual effect. There may also be an increased likelihood of seeing more colors when light pressure, such as a blindfold or sleep mask, is placed against your closed eyelids.

Other causes of closed-eye hallucinations may be related to medical conditions, including the following:

Hyponatremia

Closed-eye hallucinations have also been clinically observed as a secondary condition in people with hyponatremia. This condition causes extremely low blood sodium levels of 135 mEq/L or less.

It’s estimated that hallucinations occur in about 0.5 percent of people with sodium levels of less than 120 mEq/L, but the exact number of closed-eye hallucinations is not known.

Charles Bonnet syndrome

Visual hallucinations may also occur in Charles Bonnet syndrome. This condition leads to vision loss from macular degeneration in older adults, creating what’s sometimes called “phantom vision.”

The hallucinations experienced with Charles Bonnet syndrome may be recurring, and can last for an average of 12 to 18 months. Adults with this condition may frequently have images of people, landscapes, and objects. Each hallucination may last for just a few seconds at a time, or for several hours.

While hallucinations experienced with Charles Bonnet syndrome typically occur with the eyes open, gradual vision loss can make it feel as if the eyes are closed.

Other closed-eye hallucinations have also been reported in some people after they have surgery.

One such study found closed-eye hallucinations in a man who had minor outpatient surgery with local anesthesia. After surgery, the patient reportedly experienced hallucinations whenever he closed his eyes over a four-hour period. These closed-eye hallucinations were followed by racing thoughts for two hours.

Researchers concluded that this case was caused by a reaction to lidocaine. This is a numbing agent that may be used in minor surgeries and dental procedures. The ingredient is also sold in some over-the-counter topical numbing agents used for muscle aches and joint pain.

While hallucinations aren’t listed as a common side effect of lidocaine, other related side effects of topical applications of this medication include:

  • confusion
  • fear
  • drowsiness

Another study on heart surgery patients noted closed-eye hallucinations as rare side effects after this procedure. Researchers hypothesized that the hallucinations may be related to temporal lobe epilepsy, which causes seizures in the emotion-regulating parts of the brain. The temporal lobes also control short-term memory.

Closed-eye hallucinations aren’t typically a cause for concern. These are natural phenomena that can occur while you’re awake with your eyes closed, as well as during your sleep.

However, if closed-eye hallucinations are so significant that they cause insomnia or anxiety, consider seeing a doctor. You might also talk with a doctor if you have other unusual symptoms that affect your mood and overall cognitive function.

Closed-eye hallucinations are patterns, shapes, and colors you may witness when you shut your eyes. In most cases, these are harmless and aren’t a cause for concern. Some cases are related to medical conditions that require treatment.

Talk with a doctor if closed-eye hallucinations are accompanied by other unexplained symptoms, or if you’re experiencing significant cognitive, vision, or mood changes.