Abstract
Purpose: :
Computer vision syndrome (CVS) is a complex of eye and vision problems experienced during or related to computer use which has been reported to occur in up to 90% of computer workers. Ocular symptoms may include asthenopia, accommodative and vergence difficulties and dry eye. At ARVO 2009 (Portello et al.) we reported that symptoms following sustained computer use were significantly worse than those noted after hard copy fixation under similar viewing conditions. This may be caused by dry eye symptoms resulting from decreased blinking during computer operation. Accordingly, this study assessed both blink rate and dry eye symptoms during hard copy and computer work.
Methods: :
Ocular symptoms were assessed by written questionnaire immediately following a sustained near task. 24 young, visually-normal subjects read cognitively-demanding text aloud either from a desktop computer screen or a printed hard copy page at a viewing distance of 50cm for a continuous 20 min period. Identical text was used in the two sessions, which was matched for size and contrast. Target viewing angle and luminance were similar for the two conditions. In each trial, subjects were videotaped to determine their blink rate. Additionally, dry eye symptoms were quantified using the Ocular Surface Disease Index (OSDI) questionnaire.
Results: :
Both the mean symptom score and the symptom of blurred vision at near during the task were significantly worse for the computer condition. Mean blink rates for the computer and hard copy trials were 15.09/min and 13.63/min, respectively (p=0.16). Further, no significant change in blink rate over time was observed. While no significant difference in OSDI score was found between the two trials, there was a significant positive correlation (p=0.000) between the computer symptom score and the mean OSDI.
Conclusions: :
These results confirm the previous finding that symptoms following sustained computer use are significantly worse than those reported after hard copy fixation under similar viewing conditions. Further, these symptoms were correlated significantly with an index of ocular surface disease but not associated with decreased blinking. Future studies will examine the effect of dry eye therapies on CVS with a view to providing treatment regimens for this highly prevalent condition.
Keywords: cornea: tears/tear film/dry eye • quality of life • cornea: clinical science