Abstract
Purpose: :
Computer vision syndrome (CVS) has been reported to affect up to 90% of regular computer users. While the etiology underlying this condition remains unclear, it is frequently associated with dry eye disorders. Further, computer users may demonstrate a blink rate that is reduced by 50% when compared with general viewing. Patients with CVS are often instructed to blink more when using their computer, even though there is little evidence to support this treatment option. The aim of the present study was to determine whether increased blinking does indeed decrease symptoms associated with CVS.
Methods: :
Subjects (N=23) were required to perform a continuous 15 minute reading task on a desktop computer at a viewing distance of 50cm. Immediately following the task, they completed a questionnaire asking about ocular symptoms during the session. Two trials were completed for each subject. In the first session, no instructions were given regarding blinking. In the second session, subjects were prompted to blink at 4s intervals by means of a metronome to produce a blink rate of at least 15/min. In both trials, subjects were videotaped to determine their actual blink rate during the task.
Results: :
Mean blink rates for the metronome and control conditions were 23.5 and 11.3 blinks/min, respectively (p=0.000). Mean symptom scores for the metronome and control conditions (on a scale from 0 to 10) were 1.38 and 1.65, respectively (p=0.33). Even on the six subjects having the highest symptom scores, increased blinking did not produce a significant reduction in symptom score (2.98 versus 3.72). Interestingly, increased blinking did not produce a significant decrease in symptoms of dry eye during the task (p=0.25). However, several subjects reported that increased blinking interfered with their ability to perform the task.
Conclusions: :
An increased blink rate did not reduce symptoms of CVS significantly, either in the whole group tested or in those subjects reporting the highest symptoms scores. Further, several subjects reported that increased conscious blinking interfered with their ability to perform the task satisfactorily. If ocular dryness is indeed a significant cause of CVS, then alternative therapies, such as lubricating drops and increased ambient humidity should be evaluated.
Keywords: cornea: tears/tear film/dry eye • quality of life • cornea: clinical science