Table 6.

Composition of major ceramide species (mole percent) in meibum and tears grouped by meibum quality.

	Meibium			Tears
Fatty Acid Chain Length	Good Quality	Poor Quality	P-value	Good Quality	Poor Quality	P-value
Cer
Cer C14:0	0.09	0.12	0.21	0.12	0.11	0.15
Cer C16:0	2.12	4.54	0.006	4.69	5.30	0.49
Cer C18:1	0.15	0.24	0.05	0.54	0.65	0.18
Cer C18:0	3.27	1.86	0.001	0.62	0.58	0.47
Cer C20:0	2.23	1.26	0.001	0.52	0.54	0.50
Cer C22:0	2.75	1.79	0.001	1.30	1.08	0.29
Cer C24:1	0.75	1.40	<0.0005	1.45	1.47	0.50
Cer C24:0	3.21	2.55	0.22	2.02	1.78	0.06
Cer C26:1	0.32	0.20	0.19	0.29	0.24	0.07
Cer C26:0	1.34	1.08	0.12	0.58	0.44	0.06
Cer C16:0/C18:0	0.84*	2.10	<0.0005	7.70	10.30	0.03
Cer C16:0/C18:1	18.38*	18.94	0.60	8.81	8.31	0.05
SM
SM C14:0	1.56	1.80	0.02	1.69	1.74	0.65
SM C16:0	33.97	32.45	0.24	33.05	35.07	0.01
SM C18:1	0.49	0.66	<0.0005	0.58	0.63	0.08
SM C18:0	3.08	4.55	<0.0005	4.53	4.35	0.57
SM C20:0	2.61	3.66	<0.0005	3.91	3.38	0.04
SM C22:0	4.56	6.88	<0.0005	8.19	8.01	0.81
SM C24:1	8.69	11.77	<0.0005	8.92	10.49	0.05
SM C24:0	5.32	9.03	<0.0005	10.25	10.07	0.81
SM C26:1	0.65	0.73	0.04	0.69	0.61	0.13
SM C26:0	0.92	1.10	0.008	1.43	1.30	0.65

Cer=ceramide, SM=sphingomyelin

^*n=18 and 20, respectively due to division by 0