Reversal frequency of ambiguous figure in myopes and emmetropes A Kurtev, C Pan, M Awan |
|---|
Physiology, Saba University School of Medicine, Netherlands Antilles
|
| Myopic subjects in certain visual tasks might allocate attention more narrowly than individuals with normal eyesight (McKone et al, 2008, Perception, 37, 1765-1768). Top-down processing of ambiguous figures involves direct attention and therefore, due to committing more attentional resources to the centrally presented stimulus, may lead to different perceptual effects in myopic as compared to emmetropic subjects. We studied this possibility by measuring the reversal rate of a Necker cube under two luminance levels (low photopic and high mesopic) and using positive and negative contrast for the cube outline. Each presentation condition was preceded by adaptation period for the corresponding luminance level followed by central presentation of the Necker Cube until 25 reversals were experienced. The experimental procedure was controlled by SuperLab Stimulus Presentation System (STP100W). The results showed a trend for higher reversal rate in myopic as compared to emmetropic subjects. The presentation conditions produced significant effect that was more pronounced in myopic subjects and seemed to be dependent more on order of presentation than on actual stimulus parameters. The results are interpreted as supporting the concept of different attention strategy in myopic subjects that might affect the reversal frequency and dependence of the response on stimulus presentation conditions. |
| Up Home |
|---|