Effects of Improvements in Visual Status of Computer Users on Productivity

Abstract

Abstract: : Purpose: The aim of this project is to examine the potential connection between the astigmatic refractive corrections of subjects using computers and their productivity and comfort. We hypothesize that improving visual status results in greater productivity and improved visual comfort. Methods: Inclusion criteria required subjects 19 to 30 yrs of age. Using a double-masked, randomized design, subjects completed three experimental tasks calculated to assess the effects of vision on productivity (time to completion and the number of errors) at a computer. The tasks involved visual search tasks of: (1) counties and populations; (2) nonsense words search; and, (3) a modified text editing task. Three refractive conditions were used during the study (Best correction, control condition) and two test conditions (-1DC or –2DC axis 90 over best correction). An additional fourth test condition (uncorrected astigmatism) examined the predictive capacity of the study. A previously validated instrument was used to assess symptoms. We used non-parametric statistics to examine possible changes in productivity & comfort as a function of the refractive conditions. We also used estimates of the cost of vision care and the net change in productivity with each condition to calculate an estimated cost-benefit ratio. Results: Thirty-nine subjects participated in the study (12 males & 27 females; mean age 24.9 yrs, SD 2.4, range 21 to 30 yrs). Non-parametric analysis of variance provided evidence supporting hypotheses that differences occurred between the refractive conditions as a function of time to completion and the number of errors (p<0.0001, p<0.0001). Over the best correction, mean time to completion increased 2.5, 8.9 and 28.7% for naturally occurring astigmatic errors (mean VD error, 0.25D), -1 and –2 DC errors, respectively. Mean errors increased 17.1, 38.1 and 270.0% over best correction for the same conditions, respectively. Subjects in the –1 and –2 DC correction conditions had symptom scores 76.3 and 42.9% (less comfortable) than the best correction condition (100%), respectively. Assuming a conservative estimate of an overall 2.5% increase in productivity with appropriate refractive correction, these data suggest a favorable cost-benefit ratio of at least 2.3 for the visual correction of an employee. Conclusions: We conclude that refractive error affected both productivity and visual comfort under the conditions of this experiment. These data also suggest a favorable cost-benefit ratio for employers providing computer specific eyewear to their employees.

Keywords: refraction • clinical (human) or epidemiologic studies: tre