Visual acuity of Thai letters with and without cataract experiencing goggles

摘要

Most of the outside information is collected to us through the visual system. Since the ratio of population of elderlies to young people in Thailand is increasing rapidly, the proper infrastructure of the visual environment suitable for elderlies is one of the urgent tasks of the country. The printed labels represent visual environment and 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 elderly comes from the cloudy crystalline lens of the cataract that scatters the incoming light all over the retina and worsen the legibility of letters. The deterioration of the visual acuity investigated in the forgoing experiments should be because of the scattered light and cannot be avoided as far as the reading condition stays normal, that is the subjects read labels under illumination provided by ceiling light.