Blink patterns and lid-contact times in dry-eye and normal subjects

Figures & data

Table 1 Proportions of blink types in dry-eye (n=10) and normal (n=11) subjects

Type of blink based on lid closure	Blink types: proportions and odds ratios
	Proportions, dry eye (n=3,576)	Proportions, normals (n=1,414)	Ratio of proportions, dry eye/normals	Ratio of odds, dry eye/normals	95% confidence intervals for odds ratio	P-value for equal odds
25% blinks	0.026	0.032	0.825	0.821	(0.22, 3.05)	0.768
50% blinks	0.199	0.236	0.843	0.803	(0.33, 1.93)	0.625
75% blinks	0.349	0.331	1.057	1.087	(0.58, 2.04)	0.795
All lid closures (>0 second in duration)	0.383	0.368	1.041	1.066	(0.43, 2.62)	0.889
Extended lid closures (>0.1 second in duration)	0.015	0.032	0.463	0.455	(0.14, 1.44)	0.179
Superextended lid closures (>0.5 second in duration)	0.023	0.002	10.029	10.242	(1.38, 76.3)	0.023

Notes: Data were fitted to repeated-measurement logistic models estimated by generalized estimating equation methods. Dry-eye and normal groups were compared via odds ratios. Odds-ratio estimates, 95% confidence intervals, and P-values for the two-sided test of equal odds are presented. Group proportions and their ratios are also presented. Statistically significant (P<0.05) differences between groups are highlighted in bold.

Table 2 Mean blink rates for all blinks (or incidence) of each of the full lid-closure blink types. Note that the incidence of extended and superextended closures decreases incrementally because the percentage of these blinks to total blinks is very low

Mean blink rate	Dry eye (n=11)	Normal (n=10)	Risk ratio, dry eye/normal	95% confidence intervals for odds ratio	P-value for equal odds
All full and partial blinks (all 6 types)	28.55	13.21	2.16	(1.41, 3.31)	<0.001
All full lid closures (>0 second in duration)	14.12	6.11	2.31	(1.06, 5.04)	0.035
Extended lid closures (>0.1 second in duration)	0.548	0.509	1.078	(0.364, 3.193)	0.892
Superextended lid closures (>0.5 second in duration)	0.217	0.026	8.223	(1.729, 39.097)	0.008

Notes: Data were fitted to repeated-measurement logistic models estimated by generalized estimating equation methods. Dry-eye and normal groups were compared via odds ratios. Odds-ratio estimates, 95% confidence intervals, and P-values for the two-sided test of equal odds are presented. Group proportions and their ratios are also presented. Statistically significant (P<0.05) differences between groups are highlighted in bold.

Table 3 Mean lid-closure durations per type of blink for dry-eye and normal subjects, and duration standardized per minute to provide a mean contact rate per type of blink

Full-blink categories	Number of subjects who experienced this type of blink	Dry-eye subjects (n=11)	Normal subjects (n=10)	Risk ratio, dry eye/normals	95% confidence intervals for odds ratio	P-value for equal odds
Mean duration of lid closure/blink (seconds)
All full lid closures (>0 second in duration)	21 11 dry eye 10 normals	0.565	0.080	7.074	(2.46, 20.33)	<0.00l
Extended lid closures (>0.1 second in duration)	15 7 dry eye 7 normals	2.459	0.575	4.274	(1.65, 11.07)	0.003
Superextended lid closures (>0.5 second in duration)	6 3 dry eye 3 normals	7.134	1.589	4.490	(3.28, 6.15)	<0.00l
Contact rate*
All full blinks: contact time >0 seconds	21 11 dry eye 10 normals	4.5%	0.7%	6.377	(2.47, 16.46)	<0.00l
Extended blinks: contact time >0.1 seconds	15 7 dry eye 7 normals	4.7%	0.4%	12.572	(3.35, 47.26)	<0.00l
Superextended blinks: contact time >0.5 second	6 3 dry eye 3 normals	10.3%	0.2%	44.793	(17.73, 113.16)	<0.00l

Notes: Data were fitted to repeated-measurement logistic models estimated by generalized estimating equation methods. Dry-eye and normal groups were compared via odds ratios. Odds-ratio estimates, 95% confidence intervals, and P-values for the two-sided test of equal odds are presented. Group proportions and their ratios are also presented. Statistically significant (P<0.05) differences between groups are highlighted in bold.

* Percentages = total contact time/total observed time (standardized per minute).