Table 4. Comparison of the amount of changes in visual function and ocular fatigue between 5 and 10 lux light exposure at night.

Parameters			5 lux illumination		10 lux illumination		P value
			Mean	SD	Mean	SD
Objective parameters
	Conjunctival hyperemia
		Nasal	4.23	7.03	3.93	7.86	0.970
		Temporal	2.31	9.08	3.57	8.70	0.711
	Tear break-up time		−0.35a	1.09	−0.45a	1.21	0.912
	Maximal blinking interval		−2.60a	7.32	−1.36a	2.97	0.910
	Ocular surface temperature		−0.06a	0.56	−0.08a	0.47	0.471
Subjective parameters
	Tired eyes		0.46	1.39	0.64	1.28	0.485
	Sore/aching eyes		0.23	1.14	0.32	0.72	0.706
	Irritated eyes		0.35	1.09	0.18	1.56	0.593
	Watery eyes		−0.04a	1.61	0.04	1.67	0.993
	Dry eyes		0.23	1.39	0.00	1.44	0.789
	Eyestrain		−0.04a	1.11	0.14	0.71	0.642
	Hot/burning eyes		0.15	0.54	−0.04a	0.79	0.356
	Blurred vision		−0.19a	1.13	0.07	1.21	0.160
	Difficulty focusing		0.12	0.82	0.32	0.72	0.660
	Vision discomfort		−0.04a	0.77	0.25	0.44	0.132

SD = standard deviation, TBUT = tear break-up time.

^aDecrease after sleep under ambient light exposure.