Accommodative lag versus different stimuli

Abstract

The purpose of this study was to investigate change in accommodative lag with different stimuli such as font size, background colour, luminance contrast, fixation disparity and lens-induced accommodation in emmetropes. Accommodative responses of 86 eyes of 43 emmetropic patients were measured using the MEM retinoscopy technique while they were viewing different stimuli. The mean accommodative lag increased upon increasing font size, statistically significant (p < 0.05). The mean lag of accommodation for green as the background colour was higher when compared to the red and blue background colours, statistically significant (p < 0.05). There exists no statistical difference between the accommodative lag measured with stimuli of different contrast. The mean accommodative response was more than the accommodative demand, in the case of stereoscopic targets when used as stimuli, statistically significant (p < 0.05). The mean accommodative lag for stimuli with normal polarity was lower than those presented with reverse polarity, statistically significant (p < 0.05). The lag of accommodative response for free-space accommodative stimulus is significantly higher than the lag of accommodative response for minus lens (p < 0.05). Study suggests that when viewing a larger font, black letter on green background, 2-dimensional object and free-space stimuli, the eye tends to be comparatively in a more relaxed state.