Prospective quantification of near work using the experience sampling method

The assessment of individuals' near work by survey methods is challenging. The feasibility of the Experience Sampling Method to quantify daily visual tasks was evaluated.

Twenty-one subjects were randomly paged five times per day for 6 days. When paged, the subjects dialed into a telephone survey to report the nature, duration, and working distance of their visual activity at the time of the page.

The overall response rate was 81.3% (512/630 pages). The individual response rates varied from 6.7% to 100% (median, 86.7%). Responses were grouped into 11 categories/activities for ease of analysis. Of 506 responses, the most common activity category was "distance tasks," which included driving and walking (N = 92). Other common responses included computer use (N = 68), reading (N = 66), household tasks, e.g., cleaning, cooking, and showering (N = 64), and watching television (N = 61). Activities with a mean distance < or =26 inches (arm length) were combined as near-work responses and accounted for 54.3% (258/475) of all responses.

A modification of the Experience Sampling Method can be used to obtain a "real-time" sampling of visual activities.