Digital Eye Strain

Abstract

Digital eye strain (DES) encompasses a variety of visual and ocular symptoms that arise due to the prolonged use of digital devices. The 2023 Tear Film Ocular Surface (TFOS) Lifestyle report defined DES as “the development or exacerbation of recurrent ocular symptoms and / or signs related specifically to digital device screen viewing”. Ocular symptoms include blurred vision, diplopia, difficulty focussing at near, asthenopia, headache, tired and sore eyes, dryness, burning, tearing and irritation. A clinical evaluation of the Bernell pocket critical flicker-fusion frequency (CFF) tester was undertaken to assess its value in the field of CFF research. The device was found to have good intraexaminer repeatability and reproducibility and was used in subsequent investigations within this thesis. Two of the experimental chapters measured the impact of a novel, laptop privacy screen filter on individuals with DES. The findings showed that the privacy screen filter did not reduce DES symptoms after an intense 30- and 60-minute task. The relationship between DES symptoms, productivity, and work accuracy has previously been unclear. As shown in this thesis, symptoms increased with task duration in individuals with DES, at a faster rate for more demanding tasks. This was associated with a reduction in productivity, but not in work accuracy. A moderately positive relationship was observed between the Computer Vision Syndrome (CVS-Q), Ocular Surface Disease Index (OSDI) and the revised Convergence Insufficiency Symptom Survey (CISS) questionnaires indicating that individuals with DES are also likely to be symptomatic of dry eye disease (DED) and / or a binocular vision anomaly (BVA). Finally, the author of the thesis commenced the process of developing a new, validated DES questionnaire that, once completed, can be used globally. A comprehensive literature review, focus group studies and development of questionnaire items were all undertaken within the scope of this thesis.