The Significance of Dry Eye Signs on Preoperative Keratometry Measurements in Patients Scheduled for Cataract Surgery

Figures & data

Table 1 Order of Examinations and Description of Tests

Examinations	Description of Tests
Slit lamp	Routine slit lamp examination
Tear Osmolarity	Measured with TearLab Osmolarity System following the manufacturers recommendations
Two repeated measurements with Lenstar, Eyestar and Anterion (random order)	The time between the measurements for each device was 10–20 minutes. Measurements followed the manufacturers recommendations.
NIKBUT	Measured with Oculus Keratograph 5M following the manufacturers recommendations
OSS	Grading of OSS was based on Oxford schema, see methods for details.

Abbreviations: NIKBUT, Noninvasive keratographic break up time; OSS, ocular surface staining.

Table 2 Demography

	Group A / SDE+	Group B / SDE-	p
Subjects	89	42
Sex, percent females	65.2%	66.7%	0.7*
Mean Age, ± SD	75.6 ± 6.2	74.4 ± 6.3	0.9**

Notes: *Pearson´s Chi-squared test; **Kruskal Wallis rank sum test.

Abbreviations: SDE+, sign of dry eye positive; SDE-, sign of dry eye negative; SD, standard deviation.

Table 3 Variability for the Groups SDE+ and SDE

Device	Groups	Mean Difference in Average K/SD	Mean Difference in Magnitude of Astigmatism/SD	Percentages of > 0.25 D in Average K	Percentages of > 0.25 D of Astigmatism	Percentages of > 0.5 D of Astigmatism
Anterion	SDE+ (n=89)	0.08±0.07	0.21±0,13	5.4%	26.9%	4.3%
	SDE- (n=42)	0.09±0.07 p*=0.70	0.20±0.1 p*=0.64	4.8% p**=0.62	31% p**=0.68	0% p**=0.31
Eyestar	SDE+ (n=89)	0.08±0.08	0.21±0.17	6.5%	27.2%	9.8%
	SDE- (n=42)	0.07±0,07 p*=0.42	0.2±0.18 p*=0.65	2.4% p**=0.29	21.4% p**=0.53	11.9% p**=0.76
Lenstar	SDE+ (n=89)	0.08±0.08	0.23±0.16	6.5%	33.3%	8.6%
	SDE- (n=42)	0.06±0,06 p*=0.19	0.18±0,15 p*=0.12	0% p**=0.10	23.8% p**=0.31	2.4% p**=0.27

Notes: *Independent samples T-test, **Fisher’s exact test.

Abbreviations: SDE+, sign of dry eye positive; SDE-, sign of dry eye negative; SD, standard deviation.

Figure 1 Variability in average K compared between the groups SDE+ (group A) and SDE- (group B) for three optical biometers.

Notes: Circles indicate data points 1.5 box lengths from the edge of the box, asterisks indicate data points 3 box lengths from the edge of the box.

Figure 2 Variability of vector astigmatism between the groups SDE+ (group A) and SDE- (group B) for three optical biometers.

Notes: Circles indicate data points 1.5 box lengths from the edge of the box, asterisks indicate data points 3 box lengths from the edge of the box.

Table 4 Variability for the Groups Hyperosmolar (DEWS II) and Hyperosmolar (Study Eye)

Device	Groups	Mean Difference in Average K/SD	Mean Difference in Magnitude of Astigmatism/SD	Percentages of > 0.25 D in Average K	Percentages of > 0.25 D of Astigmatism	Percentages of > 0.5 D of Astigmatism
Anterion	Hyperosmolar (DEWS II) * (n=50)	0.08±0.07	0.22±0.13	6%	28%	6%
	Normal (n=85)	0.09±0.07 p**=0.50	0.20±0.11 p**=0.42	4.7% p***=0.71	28.2% p***=1	1.2% p***=0.14
Eyestar	Hyperosmolar (DEWS II) * (n=50)	0,09±0.10	0.22±0.17	10%	32%	10%
	Normal (n=85)	0.06±0,06 p**=0.09	0.20±0.17 p**=0.51	2.4% p***=0.10	21.4% p***=0.22	10.7% p***=0.57
Lenstar	Hyperosmolar (DEWS II) * (n=50)	0.07±0,07	0.24±0.16	4%	36%	10%
	Normal (n=85)	0.06±0.07 p**=0.58	0.20±0.16 p**=0.10	5.9% p***=1	27% p***=0.33	4.7% p***=0.29
Anterion	Hyperosmolar (Study eye) **** (n=39)	0.07±0,06	0.21±0.13	5.1%	25.6%	5.1%
	Normal (n=96)	0.09±0,07 p**=0.32	0.20±0.12 p**=0.68	5.2% p***=1	29.2% p***=0.83	2.1% p***=0.58
Eyestar	Hyperosmolar (Study eye) **** (n=39)	0.08±0.09	0.23±0.19	7.7%	33.3%	12.8%
	Normal (n=96)	0.07±0.07 p**=0.23	0.20±0.16 p**=0.35	4.2% p***=0.42	22.1% p***=0.19	9.5% p***=0.55
Lenstar	Hyperosmolar (Study eye) **** (n=39)	0.08±0,07	0.27±0.17	5.1%	43.6%	12.8%
	Normal (n=96)	0.06±0.07 p**=0.37	0.19±0.15 p**=0.01	4.2% p***=1	25% p***=0.04	4.2% p***=0.12

Notes: *Hyperosmolar (DEWS II): 308 mOsmol/L in either eye or inter eye difference of 9 mOsmol/L or more, **Independent samples T-test, ***Fisher’s exact test, ****Hyperosmolar (study eye): 308 mOsmol/L or higher in the study eye.

Abbreviation: SD, standard deviation.

Figure 3 Percentages of eyes with variability of astigmatism greater than 0.25 D for hyperosmolar and normal eyes.

Notes: *Fisher’s exact test; **Hyperosmolar: 308 mOsmol/L or higher in study eye.

Table 5 Variability for the Group NIKBUT Positive

Device	Groups	Mean Difference in Average K/SD	Mean Difference in Magnitude of Astigmatism/SD	Percentages of > 0.25 D in Average K	Percentages of > 0.25 D of Astigmatism	Percentages of > 0.5 D of Astigmatism
Anterion	NIKBUT Positive (n=21)	0.08±0.05	0.18±0.08	0%	19%	0%
	Normal (n=114)	0.08±0.07 p*=0.97	0.21±0.13 p*=0.26	6.1% p**=0.59	29.8% p**0.43	3.5% p**=1
Eyestar	NIKBUT Positive (n=21)	0.08±0.07	0.21±0.16	4.8%	23.8%	14.3%
	Normal (n=114)	0.07±0.08 p*=0.71	0.20±0.17 p*=0.89	5.3% p**=1	25.7% p**=1	9.7% p**=0.46
Lenstar	NIKBUT Positive (n=21)	0.09±0,09	0.24±0.20	14.3%	28.6%	14.3%
	Normal (n=114)	0.06±0.06 p*=0.06	0.21±0.15 p*=0.41	2.6% p**=0.048	30.7% p**=1	5.3% p**=0.14

Notes: *Independent samples T-test, **Fisher’s exact test.

Abbreviations: NIKBUT Positive, Noninvasive keratographic break up time Positive; SD, standard deviation.

Figure 4 Percentages of eyes with average K greater than 0.25 D with NIKBUT+ and NIKBUT- (normal eyes).

Note: *Fisher’s exact test statistically significant.

Abbreviations: NIKBUT, non-invasive keratography break-up time; NIKBUT+, average NIKBUT < 10 seconds; NIKBUT-, average NIKBUT > 10 seconds.

Table 6 Variability for the Groups OSS Positive (1) and OSS Positive (2)

Device	Groups	Mean Difference in Average K/SD	Mean Difference in Magnitude of Astigmatism/SD	Percentages of > 0.25 D in Average K	Percentages of > 0.25 D of Astigmatism	Percentages of > 0.5 D of Astigmatism
Anterion	OSS Positive (1) * (n=72)	0.08±0.06	0.20±0.13	4.2%	25%	2.8%
	Normal (n=63)	0.09±0.07 p**=0.56	0.21±0.12 p**=0.93	6.3% p***=0.70	31.7% p***=0.45	3.2% p***=1
Eyestar	OSS Positive (1) *(n=72)	0.08±0.08	0.22±0.18	5.6%	29.6%	11.3%
	Normal (n=63)	0.07±0.07 p**=0.60	0.19±0.16 p**=0.28	4.8% p***=1	20.6% p***=0.32	9.5% p***=0.79
Lenstar	OSS Positive (1) * (n=72)	0.07±0.07	0.23±0.16	5.6%	33.3%	8.3%
	Normal (n=63)	0.06±0.06 p**=0.33	0.19±0.16 p**=0.18	3.2% p***=0.68	27% p***=0.46	4.8% p***=0.50
Anterion	OSS Positive (2) **** (n=62)	0.78±0.64	0.78±0.64	3.2%	24.2%	3.2%
	Normal (n=73)	0.09±0.76 p**=0.23	0.93±0.76 p**=0.23	6.8% p***=0.29	31.5% p***=0.44	2.7% p***=1
Eyestar	OSS Positive (2) **** (n=62)	0.84±0.9	0.84±0.90	6.6%	31.1%	11.5%
	Normal (n=73)	0.70±0.71 p**=0.31	0.70±0.71 p**=0.31	4.1% p***=0.70	20.5% p***=0.17	9.6% p***=0.78
Lenstar	OSS Positive (2) **** (n=62)	0.74±0,68	0.74±0.68	4.8%	32.3%	8.1%
	Normal (n=73)	0.68±0.75 p**=0.65	0.68±0.75 p**=0.65	4.1% p***=0.58	28.8% p***=0.70	5.5% p***=0.73

Notes: *OSS Positive (1): Oxford grading scheme ≥ 1, **Independent samples T-test, ***Fisher’s exact test, ****OSS Positive (2): Oxford grading scheme ≥ 2.

Abbreviations: OSS Positive, ocular surface staining positive; SD, standard deviation.