An Innovative Media for Testing Visual Acuity

Peeraya Sripian, Teerapong Boonlar, Thaweesak Yingthavornsuk


The visual acuity test is a routine part of an eye examination or general physical examination, particularly if there is a change in vision or a problem with vision. In most places, the Snellen chart is used to test visual acuity in humans. The Snellen chart relies on viewing the letters or symbols from a certain distance, usually 20 feet away. Human visual acuity is then determined by the smallest letter on the chart he/she is able to identify from that viewing distance. This testing method requires a room with enough viewing distance. With the advent of new technology, computerized visual acuity testing has been proposed and used in some clinical applications. The researchers propose an innovative media to measure visual acuity in human. A hybrid image is an image that changes its meaning according to the viewing distance. It is an image composed of two different spatial frequencies; high and low spatial frequency. Based on the contrast sensitivity function, the best viewing spatial frequency is changed by the viewing distance. With this assumption, we propose the use of hybrid image as a tool to test human visual acuity. From the experiment, it was found that the hybrid images can discriminate between patients with vision problems and patients with normal vision, and that the difference detected is statistically significant.


Visual acuity measurement, Hybrid image, Computational visual illusion, Spatial frequency, Visual perception

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