Abstract
Purpose :
Vernier acuity (VA) is considered a type of visual hyperacuity because its detectable resolution in seconds of arc is considerably smaller than the diameter of a foveal cone receptor. However, the test of VA usually relies on subjective recognition. It is not clear whether ocular motor system, such as OKN, responds to this type of stimulus. It can be an objective measurement of VA if it does. We will report the characteristics of OKN induced by dynamic vernier stimulus
Methods :
a vernier stimulus pattern consists of horizontal black and white bars on which vertical offsets on the bars was displayed. A high resolution TV screen was used to display the vernier stimulus. The size of the screen was 7.9x4.5 ,9.4x5.3,11.7x6.7 and 15.4x8.9 degrees horizontal and vertically when is was set at 12meters,10meters,8meters and 6meters from subjects. When the stimulus pattern moved, the movement of vernier offsets was visible. Different sizes of the offsets, velocity, and lighter/dark environment were used for the experiment. An eye movement recording system (FNND, USA) was used to record the OKN. 5 subjects participated in the experiment.
Results :
OKN eye movements were recorded when the environment is brighter, and when the stimulus velocity is lower than 2.5 degrees/seconds, and when the resolution of the offsets was larger than 15 seconds of arc. The velocity of the average OKN eye movements was 1.5 degrees/seconds.
Conclusions :
it is revealed that the OKN responds to hyperacuity stimulus. This may allow measurement of VA in pre-verbal infants and research on neural processing of cortical visual function in animals since VA is involved in cortical processing.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.