Effect of Ultra-high-definition Television on Ocular Surface and Fatigue.PURPOSE
 To investigate the effects of watching ultra-high-definition television (UHD TV) on subjective ocular fatigue and objective ocular surface indices.


 A total of 76 volunteers were recruited for this study.  Subjects watched UHD TV for 10 minutes at a viewing distance of 110 cm.  Best-corrected visual acuity, refractive errors, tear break-up time, corneal staining grading, conjunctival redness grading by slit-lamp examination, tear meniscus measurement by anterior segment optical coherence tomography, and ocular symptom scores were obtained before and immediately after watching UHD TV.  Subgroup analyses were conducted according to participant age (old age group &gt;50 years vs. young age group ≤50 years) and dry-eye syndrome (presence vs. absence).  The relationship between subjective and objective indices was evaluated.


 The mean age of subjects was 39.6 ± 12.4 years.  Watching UHD TV induced a decrease in tear break-up time in the non-dry-eye group (p &lt; 0.001) but not in the dry-eye group (p = 0.726).  Corneal staining grades increased in all subgroups, and the changes were particularly larger in the older group (p = 0.038).  The increase in ocular symptom scores was larger in the dry-eye group (p = 0.08) and in the older group (p = 0.016).  The decrease in tear break-up time and ocular symptom scores after watching UHD TV was significantly correlated with tear break-up time.


 CONCLUSIONS
 Tear break-up time significantly decreased in non-dry-eye subjects after watching UHD TV.  Subjective ocular discomfort increased significantly in subjects over the age of 50 and in participants with dry-eye syndrome.
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