The colorful geometric patterns you experience upon waking up are a type of visual phenomenon known as hypnagogic hallucinations. These hallucinations occur during the transition between wakefulness and sleep, specifically during the hypnagogic state. The hypnagogic state is a transitional period when you are just starting to fall asleep, but your brain is still somewhat active.
There are several factors that can contribute to these hypnagogic hallucinations:
Brain Activity: During the hypnagogic state, your brain is in a unique state of flux, with a mix of wakefulness and sleep-related brainwave patterns. This combination of neural activity can result in visual perceptions that are not based on external stimuli.
Sensory Deprivation: When you wake up, your eyes are initially closed, and your brain might not immediately receive a lot of visual input from the external world. This sensory deprivation can lead to the brain generating its own visual experiences.
Dream-Like Elements: As you transition from sleep to wakefulness, you might still retain some dream-like elements in your consciousness. These elements can manifest as colorful and abstract geometric patterns.
Neural Excitation: Certain brain areas, such as the visual cortex, may experience bursts of neural activity during this transitional state, which can produce visual sensations even with closed eyes.
Hypnagogic hallucinations are relatively common and usually harmless. They can vary in intensity and content from person to person. The hallucinations typically last only a brief moment before fading away as you fully wake up and your brain shifts into a more alert state. Some people may also experience hypnopompic hallucinations, which are similar visual phenomena that occur during the transition from sleep to wakefulness.
It's essential to note that occasional hypnagogic hallucinations are considered normal. However, if you find that these experiences are frequent, intense, or accompanied by other unusual symptoms, it might be a good idea to discuss them with a healthcare professional to rule out any underlying medical or sleep-related issues.