Both saccadic and manual responses in the amblyopic eye of strabismics are irreducibly delayed

• DOI: 10.1167/18.3.20
• Publication Date: 2018-04-20T16:35:13Z
• Authors: Christina Gambacorta; Jian Ding; Suzanne P. McKee; Dennis M. Levi
• Keywords: Stimulus (psychology)

Abnormal early visual development can result in a constellation of neural and deficits collectively known as amblyopia. Among the many deficits, common finding is that both saccadic manual reaction times to targets presented amblyopic eye are substantially delayed when compared fellow or normal eyes. Given well-known contrast sensitivity eye, natural question whether prolonged simply consequence reduced stimulus visibility. To address this question, Experiment 1 we measure (RT) perifoveal stimuli function effective (i.e., scaled by eye's threshold). We find sensory differences between eyes minimized, asymptotic RTs our anisometropic amblyopes were similar two However, results suggest some strabismic have an irreducible delay at asymptote. That is, even accounted for, these observers still had large interocular (on average, 77 ms) time. In 2, assess role fixation on time with without foveal target (the “gap effect”). Our that, while removing does indeed speed up gap effect Therefore, not eliminate eye. Finally, 3 same observers. This allowed us determine relationship latencies modalities. found strong correlation times; however, RT difference about half RT, suggesting there may be separable effects time: (a) central problem directing actions target, related disengagement attention fovea, which delays times, (b) further because motor refractory period from previous saccade microsaccade, made attempt stabilize strabismics.