Proper-Sized Thai Letters On Different Background Contrasts And Illumination Environment Suitable For Elderlies

Abstract

Printed labels represent visual environment as they are the targets for getting information of the products. They have been found to be expressed by so small letters and are too difficult for elderlies to read. A serious problem of the visual performance of the elderlies come from the cloudy crystalline lens of the cataract that scatters the incoming light all over the retina. The cataract experiencing goggles composed of color filter, brightness filter, and haze filter that together simulate the elderly vision with cataract. This study experimented on young observers wearing cataract experiencing goggles for the result of elderlies cataract vision on Thai letters legibility. The Thai letters test charts of varying letter sizes for adjustment experiment method made into 3 sets of different backgrounds. The one-room and two-room experimental techniques for different illumination environment study was experimented. Different background contrasts gave different results especially the lower contrast gave worse result for the cataract vision. The two-room technique preserves cataract vision to be as good as normal vision.