Researchers from the University Hospital Bonn and the University of Bonn have unveiled how subtle eye movements and photoreceptor density influence sharp vision. The fovea, a central region of the retina, is essential for clear vision, containing densely packed cone photoreceptors that detect minute details. The study, published in eLife, utilized high-resolution imaging and micro-psychophysics to explore this relationship. Each person possesses a unique cone density pattern in their fovea, and their eyes engage in continuous minor movements, even while fixating on a stationary object. These fixational eye movements, particularly drift, adjust the retina’s position to enhance visual acuity by aligning with areas of higher cone density. The researchers, using a sophisticated adaptive optics scanning light ophthalmoscope (AOSLO), studied the eye movements of 16 participants during a visual discrimination task. They found that the spatial arrangement of cones only partially predicts visual resolution and confirmed that eye movements are finely tuned to maximize sampling through the foveal cones. These insights could significantly impact understanding ophthalmological conditions and inform the development of technologies like retinal implants aimed at restoring vision. The work was supported by various foundations including the German Research Foundation and the Carl Zeiss Foundation.
