Experiencing waves or other visual disturbances in your peripheral vision after staring at something for a prolonged period is a relatively common phenomenon, and it is often referred to as the "Troxler effect" or "Troxler's fading." This effect is a result of how our visual system works and is considered normal.
The Troxler effect occurs when you fixate your gaze on a particular point or object for an extended period. As a consequence, the cells in your eyes that detect that specific image become fatigued and stop responding as strongly. Meanwhile, the surrounding cells that detect other parts of the visual scene continue to fire normally. This imbalance can lead to a perception of fading or waving in your peripheral vision.
Additionally, other factors like eye fatigue, tiredness, or the lighting conditions in your environment may exacerbate these visual disturbances.
In most cases, the Troxler effect is harmless and temporary. When you shift your gaze or look away from the fixed point, your peripheral vision will return to normal relatively quickly. However, if you are concerned about any persistent or severe visual disturbances, it's always a good idea to consult with an eye care professional to rule out any underlying issues.