Table 3.

Published studies to date that have examined the impact of blue light-filtering spectacles on DES

Author and year	Participants and methods	Key findings
Cheng et al, 2014101	n=20 ‘dry eye’ participants with reduced Schirmer test values. n=20 with normal Schirmer values. Wraparound goggles with low-blocking, medium-blocking and high-blocking properties worn for computer work for 1 week each. Schirmer test and subjective questionnaire completed after each week.	No significant change in Schirmer test values for any group or filter. Dry eye participants showed a reduction in ocular complaint scores with all filter levels.
Ide et al, 201531	n=33 participants in three groups of 11. Each group wore either high-blocking, low- blocking or control lenses. Intensive 2-hour computer task completed, with CFF and subjective complaints measured pretask and post-task.	Control group showed significant post-task worsening of CFF compared with high-blocking and low-blocking groups. No difference in subjective complaints between the three groups.
Lin et al, 201729	n=36 participants in three groups of 12. Each group wore no blocking, low-blocking or high-blocking spectacles for 2-hour computer task. CFF and questionnaire completed pretask and post-task.	Post-task reduction in CFF significantly less in high block group. No difference in CFF change between low-block and no block groups. High-block group reported less pain around/inside the eyes and less feelings of itchy eyes post-task compared with other groups.

CFF, critical flicker–fusion frequency; DES, digital eyestrain.