Purchase this article with an account.
Jingjing Xu, Zhili Zheng, Hao Chen, Bjorn Drobe; The effect of spatial frequency on accommodation of myopes and emmetropes in near-detection threshold conditions. Invest. Ophthalmol. Vis. Sci. 2014;55(13):780.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To investigate the effect of spatial frequency (SF) on accommodation in near-detection threshold tests in emmetropes and myopes.
Twelve emmetropic (EMM) and thirteen myopic (MYO) adults were recruited. Sine wave Gabor targets of 2, 4, 6, 8, 12, 16 cpd spatial frequencies were presented from a tablet computer at 40 cm. The horizontal and vertical grating targets were presented in contrast-descending random order. Subjects were asked to choose the direction of gratings with a gamepad. Detection thresholds for each spatial frequency were determined by the mean value of three measurements of the contrast sensitivity function. While each grating was presented with a measured detection threshold, accommodation responses were recorded continuously using the Grand Seiko WAM-5500 autorefractor for 30 seconds at 5 Hz.
Detection thresholds were lowest for 16 cpd and highest for 4 cpd (EMM: F=70.45, p<0.001; MYO: F=79.14, p<0.001). EMMs and MYOs had similar detection thresholds (p>0.1). The average accommodative responses to detection threshold contrast targets of two groups were -1.96±0.07D (EMM) and -1.96±0.03D (MYO). In the emmetropic group, accommodative responses to targets of 2 and 4 cpd were higher compared to other SFs (F=2.37, p=0.05), but not in myopes. Emmetropes had smaller variations of accommodation (AMF, defined as SD of accommodative response) than myopes for 12cpd (t=-4.763, p=0.001). In the myopic group, AMF of 8cpd was lowest, while in the emmetropic group, AMF of 12cpd was lowest.
Emmetropic and myopic adults had similar contrast sensitivity functions for near presentations. Accommodative responses in emmetropes seem more sensitive to near-detection threshold grating targets than in myopes.
This PDF is available to Subscribers Only