A comparative study of the quality of non-stimulated and stimulated tears in normal eye male subjects using the tear ferning test

Figures & data

Figure 1 Box plots for the tear ferning grades for non-stimulated and stimulated tears.

Note: TF patterns were graded using 0.1 increments.
Abbreviations: TF, tear ferning; NTF (OD), tear ferning for non-stimulated tears collected from the right eye; NTF (OS), tear ferning for non-stimulated tears collected from the left eye; STF (OD), tear ferning for stimulated tears collected from the right eye; STF (OS), tear ferning for stimulated tears collected from the left eye.

Figure 2 Representative tear ferning images of non-stimulated tears collected from the right and left eyes of the same subject.

Abbreviations: NTF (OD), tear ferning for non-stimulated tears collected from the right eye; NTF (OS), tear ferning for non-stimulated tears collected from the left eye.

Figure 3 Representative tear ferning images of stimulated tears collected from the right and left eyes of the same subject.

Abbreviations: STF (OD), tear ferning for stimulated tears collected from the right eye; STF (OS), tear ferning for stimulated tears collected from the left eye.

Table 1 Ocular surface disease index, tear meniscus height, non-invasive tear break-up time, and tear ferning scores

Test	Median (IQR)
OSDI	40.00 (6.00)
TMH (OD; mm)*	0.25 (0.06)
TMH (OS; mm)*	0.25 (0.05)
NITBUT (OD; s)*	9.80 (5.33)
NITBUT (OS; s)*	10.00 (5.90)

Note: *P>0.05.

Abbreviations: IQR, interquartile range; OSDI, ocular surface disease index; TMH, tear meniscus height; NITBUT, non-invasive tear break-up time; OD, right eye; OS, left eye.

Table 2 Tear ferning grades

TF grade*	Median (IQR)
	Non-stimulated tears	Stimulated tears
TF (OD)	0.55 (0.89)	0.65 (0.99)
TF (OS)	0.50 (1.11)	0.70 (1.15)

Notes: *P>0.05. TF patterns were graded using 0.1 increments.

Abbreviations: IQR, interquartile range; TF, tear ferning; OD, right eye; OS, left eye.

Table 3 Correlations among the ocular surface disease index, tear meniscus height, and non-invasive tear break-up time scores

Test/Correlation	OSDI	TMH (OD)	TMH (OS)	NITBUT (OD)	NITBUT (OS)
OSDI
r	1	‒0.002	0.055	‒0.239	0.004
P	—	0.992	0.743	0.149	0.981
TMH (OD)
r	‒0.002	1	0.577*	0.092	0.151
P	0.992	—	0.001	0.581	0.364
TMH (OS)
r	0.055	0.577*	1	0.057	0.183
P	0.732	0.001	—	0.732	0.272
NITBUT (OD)
r	‒0.239	0.092	0.057	1	0.610*
P	0.144	0.581	0.732	—	0.001
NITBUT (OS)
r	0.004	0.151	0.183	0.610*	1
P	0.981	0.364	0.272	0.001	—

Note: *Correlation is significant at the 0.01 level (two-tailed).

Abbreviations: r, Spearman correlation coefficient; P, significance; OSDI, ocular surface disease index; TMH, tear meniscus height; NITBUT, non-invasive tear break-up time; OD, right eye; OS, left eye.

Table 4 Correlations among the TF grades obtained from non-stimulated and stimulated tears

Test/Correlation	Non-stimulated tears		Stimulated tears
	TF (OD)	TF (OS)	TF (OD)	TF (OS)
Non-stimulated tears
TF (OD)
r	1	0.554*	0.275	0.291
P	—	0.007	0.094	0.076
TF (OS)
r	0.554*	1	0.262	0.275
P	0.007	—	0.112	0.095
Stimulated tears
TF (OD)
r	0.275	0.262	1	0.491*
P	0.094	0.112	—	0.002
TF (OS)
r	0.291	0.275	0.491*	1
P	0.076	0.095	0.002	—

Note: *Correlation is significant at the 0.01 level (2-tailed). TF patterns were graded using 0.1 increments.

Abbreviations: r, Spearman correlation coefficient; P, significance; TF, tear ferning; OD, right eye; OS, left eye.