Table 2.

Comparison of symptoms and tear characteristics for control and patient groups (mean/median), together with the significance of their differences (ANOVA/Friedmann). Noninvasive tear breakup time (NIBUT) values are extrapolated from logarithmically transformed data.

	Diabetes	Healthy controls	ANOVA/Friedmann  (P values)
McMonnies questionnaire  (mean ± SD)	8.8 ± 6.7	7.6 ± 4.6	0.33
Lipid layer thickness grade (median)	2	3	0.02
NIBUT (s) (mean ± SD)	6.0 ± 1.9	8.2 ± 2.5	<0.0001
Phenol red thread test (mm) (mean ± SD)	13.7 ± 4.7	16.3 ± 4.9	0.01
Corneal sensitivity threshold (mBAR)	1.3 ± 1.3	0.2 ± 1.3	<0.001