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A double-blind test of blue-blocking filters on symptoms of digital eye strain.

BACKGROUND
Many ophthalmic lens manufacturers are currently marketing blue-blocking filters, which they claim will reduce symptoms of Digital Eye Strain (DES). However, there is limited evidence to support the proposal that DES results from the blue light emitted by electronic screens.


OBJECTIVE
This investigation compared the effect of blue-blocking filters on DES symptoms with a no-filter lens, using a double-blind methodology.


METHODS
24 subjects were required to perform a 20-minute reading task from a tablet computer. They wore either lenses containing a blue-blocking filter (TheraBlue 1.67 or TheraBlue polycarbonate) or a CR-39 control lens which did not include a filter. Immediately following each session, subjects completed a questionnaire to quantify symptoms of DES.


RESULTS
While a significant increase in symptoms was observed immediately following the near vision task (p = 0.00001), no significant difference in symptoms was found between the 3 lens conditions (p = 0.74).


CONCLUSIONS
There is little evidence at this time to support the use of blue-blocking filters as a clinical treatment for DES. Management of other ocular factors, as well as the creation of an optimal environment for screen viewing, are more likely to provide greater success in minimizing symptoms.