A new study reveals how tiny, involuntary flickers sharpen vision, challenging old assumptions and opening doors for new science and tech.
Eyes are never still—and that’s a good thing, according to new research.
A study published in Proceedings of the National Academy of Sciences (PNAS) on February 11, 2025, has revealed that small, unconscious eye movements known as fixational eye movements (FEM) play a crucial role in enhancing visual acuity. These findings challenge the traditional assumption that FEM primarily introduce blur, instead highlighting their role in fine detail perception.1
What the research shows
Researchers combined theoretical models with experimental data to analyze how FEM influence retinal coding and human visual acuity. Using an adaptive optics scanning laser ophthalmoscope, they tracked FEM in healthy subjects performing visual discrimination tasks.
The study found that while FEM introduce variability in retinal ganglion cell activity, they also help preprocess visual input, effectively enhancing the brain’s ability to encode fine details.
The study proposes a balance between two opposing mechanisms: one where FEM disrupt visual perception by adding noise to retinal signals, and another where they facilitate better visual encoding by refreshing receptive fields in the retina. The researchers demonstrated that FEM enhance acuity for stimuli as small as receptive field size or smaller, providing a significant benefit for detailed vision.
Moreover, the study observed that human subjects naturally adjust FEM amplitudes based on stimulus size, keeping them within an optimal range that maximizes visual sharpness. The findings align with previous research indicating that artificially stabilizing visual stimuli on the retina impairs acuity, reinforcing the idea that a certain degree of motion is necessary for optimal perception.
Tiny movements, massive implications
Beyond fundamental vision science, these findings could have far-reaching implications.
In clinical settings, understanding how FEM contribute to visual processing may improve diagnostic approaches for visual impairments and help refine corrective strategies for conditions such as amblyopia or presbyopia. Additionally, this research could enhance the development of next-generation retinal prosthetics and visual aids that take advantage of FEM-driven image optimization.
The study’s insights also suggest potential applications in artificial vision systems. Engineers working on computer vision and machine learning algorithms could model FEM-like processes to improve the clarity and precision of visual data captured by cameras or robotic systems.
By mimicking these tiny eye movements, future technology may achieve higher resolution and more dynamic image processing, benefiting fields ranging from augmented reality to autonomous navigation.
Furthermore, these findings offer new perspectives on neural processing and visual attention. FEM not only assist in refining visual acuity but may also play a role in perceptual learning and adaptation, suggesting that they contribute to the brain’s ongoing efforts to optimize sensory input.
This raises intriguing questions about how these micro-movements interact with higher-order cognitive functions and whether they can be harnessed to enhance vision-based learning strategies.
These results contribute to a growing body of evidence suggesting that vision is an active process even at the smallest scales. Understanding the role of FEM in visual acuity could have implications for fields such as ophthalmology, vision correction and neural processing studies.
As researchers continue to uncover the complex interplay between eye movements and perception, their findings may lead to innovative advancements in both medical and technological fields, further refining our understanding of how we see the world.
Reference
- Nghiem TAE, Witten JL, Dufour O, et al. Fixational eye movements as active sensation for high visual acuity. PNAS. 2025:122(6);e2416266122.
