Functional vision: ‘Real world’ impairment examples from the SKI Study

Abstract

The Smith-Kettlewell Institute (SKI) Study of vision in elders demonstrates that while standard high contrast visual acuity holds up well even into advanced old age, vision under the non-ideal conditions found in the real world (low contrast, glare, low luminance) falls off much more rapidly. The present article illustrates the functional impact of these findings by presenting typical real world scenes viewed with a filter that reduces contrast sensitivity to the level of the average 80 year old, as well as a second filter that more profoundly reduces contrast sensitivity and thus simulates vision of the aged cataractous eye. The impact on face recognition is also shown. It is clear from the study results and the simulations that, in effect, many older people with good acuity are visually impaired in performing everyday tasks.