Yaw Buabeng¹ (yaw.buabeng@uga.edu), Billy Hammond¹; ¹University of Georgia

This study assessed vernier performance across wavelengths and at different broadband intensity levels to determine whether hyperacuity depends primarily on photopic drive or varies systematically with spectral composition. Twenty healthy young adults (mean age = 24.8 ± 2.3 years) with normal, corrected vision were tested in an aperture defined vernier task. Narrowband stimuli (420–660 nm) and a broadband intensities were produced by a 1000-W Xenon arc lamp with interference filters. Thresholds, defined as the minimum detectable misalignments between two visual targets, were recorded using a digital micrometer. Vernier thresholds did not vary significantly with wavelength (F (6,98) = 0.628, p = 0.71). Similarly, vernier thresholds did not vary significantly with the different broadband intensities (F (5,24) = 0.26, p = 0.93). The stability of vernier acuity across these conditions indicates that hyperacuity performance is independent of spectral composition or photopic drive. This consistency supports the established view that vernier acuity is a hyperacuity mediated primarily by cortical neural mechanisms rather than by retinal sampling or luminance-dependent factors.