Table 4.

Spearman’s Rho (ρ) coefficients between sphingolipid pmole and dry eye (DE) symptoms and signs.

Spearman’s ρ	DE Symptoms		MGD/DE Signs
	DEQ-5	OSDI	Meibomian Quality	Eyelid Vascularity	Meibomian Dropout	Meibomian Plugging	TBUT	Fluorescein Stain	Schirmer Test	MMP
In meibum (total pmole)
Cer	−0.37**	−0.38**	0.46***	−0.16	0.37***	0.23	0.03	−0.02	0.32*	0.12
Hex-Cer	−0.21	−0.25	0.40**	−0.09	0.28	0.15	0.13	−0.15	0.37***	−0.05
SM	−0.30*	−0.32*	0.66***	0.03	0.37***	0.03	−0.08	0.0	0.15	−0.03
Sph	0.02	−0.09	0.13	−0.06	0.10	0.31*	0.02	0.06	0.22	0.19
Sa	−0.21	−0.23	0.31*	−0.28	0.17	0.23	0.17	−0.06	0.30*	−0.03
SPL	−0.27	−0.21	0.64***	−0.28	0.34*	0.20	0.003	−0.12	0.31*	−0.02
In tears (total pmole)
Cer	−0.12	−0.06	0.04	−0.09	0.15	0.09	−0.19	0.12	−0.42	−0.046
Cer/SM	0.08	0.08	−0.14	−0.01	−0.08	−0.11	−0.06	−0.006	−0.40**	0.04
Hex-Cer	−0.10	0.005	0.17	−0.28	0.25	0.22	−0.18	0.21	−0.03	0.03
Hex-Cer/SM	−0.02	0.07	0.07	−0.20	0.20	0.20	−0.007	0.18	−0.01	0.09
SM	−0.20	−0.11	0.11	−0.14	0.23	0.16	−0.21	0.14	−0.33*	−0.09
Sph	−0.19	0.005	0.32	−0.32	0.20	0.18	−0.02	0.14	0.10	−0.14
S1P	0.18	0.31	−0.17	−0.08	−0.01	0.03	0.03	0.07	−0.003	−0.03
SPL	−0.16	−0.05	0.07	−0.14	0.19	0.14	−0.19	0.14	−0.32*	−0.07

DE=Dry Eye, SPL=total sphingolipid, Cer=ceramide, Hex-Cer=hexosyl ceramide, SM=sphingomyelin, Sph=sphingosine, Sa=sphinganine, S1P=sphingosine 1-phosphate, TBUT=Tear Break-Up Time, MMP=Matrix Metallopeptidase-9, OSDI=Ocular Surface Disease Index, DEQ-5=Dry Eye Questionnaire, ρ Rho=coefficient for dependent variables

^*Statistically significant difference at p-values <0.05

^**p-value <0.01

^***p-value <0.001.