Date: Wednesday, 30.10.2024 15:20-17:00 CET
Location: Building S1|15 Room 133
Abstract:
The centermost 1 degree of the visual field, the foveola, plays a vital role for our visual experience because it is the region which resolves visual information with the highest spatial resolution. Despite its unique relevance, however, little is known about visual function inside the foveola. Testing sensitivity at such a small scale is challenging because incessant, small eye movements at the lower limit of standard eye trackers prevent testing adjacent locations in isolation. Hence, even in the smallest visual field tests (i.e. perimetries), the entire foveola is represented by only a single data point. Here, we developed a new perimetrical approach to map visual sensitivity across the foveola using a high-precision digital dual Purkinje image eye tracker with real-time control of the retinal input. Observers were asked to detect a brief probe (50 ms, 5 arcmin, background: 10 cd/m2) of varying contrast which was presented at one of 13 retinal locations within 1 degree of their preferred retinal locus. We validated our approach by rigorously sampling individual psychometric functions at each retinal location of N=11 observers. We find that foveolar sensitivity patterns are vastly different both within as well as across individuals, and that peak sensitivity is consistently shifted away from the preferred retinal locus. Our results provide new insights into visual information processing at the foveolar scale, and pave the way for new clinical and scientific applications.
