Efficient saccade enhances performance in clinical dynamic visual acuity test

To investigate the eye movement pattern across different speeds during clinical dynamic visual acuity (DVA) tests and their relationship with dynamic visual performance.

Twenty young adults with normal or corrected-to-normal visual acuity underwent clinical DVA tests at 20, 40, 60, and 80 degrees per second (dps). Eye movement was recorded using a table-mounted eye tracker. Smooth pursuit- and saccade-related parameters were calculated from the gaze trace, and the relationships between eye movement parameters and dynamic visual performance were analyzed.

DVA was significantly better at 20 dps than at higher speeds (p < 0.05 for all comparisons). Eye movement patterns and parameters varied with target velocity, as smooth pursuit dominated at low speeds and saccades became more prominent at high speeds. At 20 dps, DVA correlated negatively with saccade displacement (r = -0.523, p = 0.022) and displacement per saccade (r = -0.528, p = 0.020). During the DVA test at 80 dps, positive correlations emerged between DVA and saccade period (r = 0.521, p = 0.022), duration (r = 0.500, p = 0.029), and displacement (r = 0.483, p = 0.036). Increased saccade episode (β = 0.540, p < 0.001) and time (β = 27,333, p < 0.001) were associated with greater odds of identification error at 20 dps. At 80 dps, higher smooth pursuit velocity was associated with increased odds of identification error (β = 0.030, p = 0.016).

Eye movement strategies adapt dynamically to target speed. Quick and efficient saccades support improved dynamic visual performance, although high-amplitude saccades and pursuit velocity disrupted tracking at high speeds. These findings offer insights for optimizing clinical DVA tests and enhancing the clinical utility of DVA as a functional vision indicator.