Table 2.

Values of all the parameters under study before (pre) and after (post) the instillation of saline solution (control) and 0.2% benzalkonium chloride (BAC) for 5 days.

Parameter	Group	Mean ± SD		P value
		Pre	Post
Tear secretion without anesthesia (μL)	Control	11.90 ± 2.89	8.40 ± 4.12	0.032∗
	0.2% BAC	9.60 ± 3.13	17.80 ± 4.69	0.008∗
Tear secretion with anesthesia (μL)	Control	5.80 ± 1.03	6.00 ± 1.15	0.414
	0.2% BAC	6.60 ± 0.52	4.60 ± 0.84	0.004∗∗
Tear breakup time (s)	Control	5.03 ± 1.82	3.90 ± 1.39	0.036∗∗
	0.2% BAC	4.30 ± 1.15	1.27 ± 0.34	0.005∗∗
Tear osmolarity (mOsm/L)	Control	309.70 ± 13.66	332.80 ± 13.49	0.008∗
	0.2% BAC	313.00 ± 12.75	296.10 ± 11.71	0.014∗
Corneal staining (score)	Control	1.40 ± 0.70	1.70 ± 0.95	0.405
	0.2% BAC	1.40 ± 0.70	4.00 ± 0.00	0.004∗∗
Conjunctival hyperemia (score)	Control	0.10 ± 0.32	0.10 ± 0.32	1.000
	0.2% BAC	0.30 ± 0.68	3.40 ± 0.52	0.004∗∗
Density of goblet cells (cells/mm2)	Control	683.57 ± 77.63	636.19 ± 140.20	0.304
	0.2% BAC	703.12 ± 75.76	250.89 ± 77.71	<0.001∗
Height of mucin cloud (μm)	Control	27.48 ± 0.74	26.71 ± 0.79	0.469
	0.2% BAC	27.72 ± 0.54	15.76 ± 0.63	<0.001∗
Expression levels of IL-6 (fold change)	Control	0.020 ± 0.031	0.017 ± 0.008	0.770
	0.2% BAC	0.032 ± 0.063	0.322 ± 0.252	0.002∗∗

Statistical comparison was done between pre and postvalues. ^∗P < 0.05, Student's t-test for paired samples. ^∗∗P < 0.05, the Wilcoxon signed-rank test.