Mikroszemmozgások

Mikroszemmozgások, often translated as microsaccades, are tiny, involuntary, rapid eye movements that occur constantly while a person is looking at a stable visual target. These movements are much smaller and faster than saccades, which are the larger, voluntary movements used to shift gaze from one point to another. Microsaccades are fundamental to how we perceive the visual world.

These subtle shifts in gaze play a crucial role in maintaining visual acuity. When our eyes are perfectly still, the image on the retina begins to fade due to photoreceptor adaptation. Microsaccades constantly move the image across the retina, preventing this fading and ensuring that we continue to perceive the scene. Without them, we would experience a phenomenon called the Troxler effect, where peripheral stimuli disappear from view.

The exact neural mechanisms controlling microsaccades are still a subject of research, but they are believed to originate in the brainstem and are influenced by various cortical areas. They occur at a rate of about 1-3 per second and have amplitudes typically ranging from a few arcminutes to several degrees of visual angle. Microsaccades are not random; their direction and size are influenced by the visual input and cognitive tasks being performed.

Studies have shown that microsaccade characteristics can be altered in certain neurological and psychiatric conditions, such as schizophrenia and Parkinson's disease, making them a potential biomarker for diagnostic and research purposes. Understanding microsaccades provides valuable insights into the dynamic nature of visual perception and the complex interplay between eye movements and brain function.