Table 2.

Changes in ocular indices after watching ultra-high-definition television

Variable*	Total		Dry eye		Non-dry eye		p-value‡	Old age		Young age		p-value‡
	Mean ± SD	p-value†	Mean ± SD	p-value†	Mean ± SD	p-value†		Mean ± SD	p-value†	Mean ± SD	p-value†
Best-corrected visual acuity (logMAR)	-0.00 ± 0.08	0.675	-0.01 ± 0.09	0.352	+0.01 ± 0.08	0.595	0.300	+0.02 ± 0.08	0.303	-0.01 ± 0.09	0.260	0.147
Refractive errors (SE, diopters)	-0.03 ± 0.17	0.147	-0.05 ± 0.22	0.163	-0.00 ± 0.06	0.714	0.240	+0.08 ± 0.06	0.181	-0.05 ± 0.20	0.081	0.122
Tear break-up time (sec)	-1.08 ± 2.24	<0.001	+0.01 ± 1.77	0.726	-2.46 ± 1.93	<0.001	<0.001	-1.25 ± 2.19	0.010	-1.00 ± 2.28	0.003	0.654
Corneal staining grading (0–3)	+0.17 ± 0.41	0.001	+0.20 ± 0.40	0.003	+0.14 ± 0.43	0.048	0.586	+0.21 ± 0.51	0.039	+0.15 ± 0.36	0.004	0.038
Conjunctival redness grading (0–3)	+0.05 ± 0.26	0.127	+0.09 ± 0.27	0.051	+0.00 ± 0.24	>0.999	0.156	-0.00 ± 0.29	>0.999	+0.07 ± 0.24	0.510	0.298
Tear meniscus height (μm)	-9.5 ± 99.8	0.408	+8.1 ± 95.1	0.132	-24.6 ± 102.4	0.618	0.156	-33.3 ± 127.4	0.213	+1.5 ± 83.2	0.900	0.159
Tear meniscus area (μm2)	-1,184 ± 18,688	0.582	-4,146 ± 20,612	0.205	-2,286 ± 15,734	0.396	0.136	-3,750 ± 22,223	0.417	+0.0 ± 16,920	>0.999	0.420
Ocular symptom score	-0.91 ± 10.66	0.460	+1.34 ± 9.36	0.364	-3.54 ± 11.60	0.08	0.046	-5.21 ± 15.15	0.106	+1.08 ± 7.14	0.282	0.016

Dry eye = tear break-up time <8 seconds; Non-dry eye = tear break-up time ≥8 seconds; Old age = age >50 years old; Young age = age ≤50 years old; SD = standard deviation; log-MAR = logarithm of the minimum angle of resolution; SE = spherical equivalent.

^*Values obtained after watching with the subtraction of baseline values;

^†Paired t-test;

^‡Linear mixed model.