Comparison of corneal sensitivity, tear function and corneal staining following laser in situ keratomileusis with two femtosecond laser platforms

Figures & data

Table 1 Patient data and preoperative ocular parameters

Flap creation	Mean age, range (years)	Sex (n)		Eyes (n)	Mean SER ± SD (D)	Mean K ± SD (D)
		Male	Female
VisuMax	28.8, 21–39	20	25	45	−4.94 ± 2.08	44.16 ± 1.81
IntraLase™				45	−4.91 ± 2.09	44.02 ± 1.61
P-value	–	–	–	–	0.94	0.26

Notes: VisuMax (Carl Zeiss Meditec, Jena, Germany) and IntraLase™ (Abbott Medical Optics Inc, Santa Ana, CA, USA).

Abbreviations: SER, spherical equivalent refraction; SD, standard deviation; K, keratometry; D, diopter.

Table 2 Changes over time in corneal sensitivity following VisuMax or IntraLase™ LASIK

Preop						1 month					3 months
Level of myopia	Flap creation	Mean (cm)	95% CI		P	Mean (cm)	95% CI		Change to preop (%)	P	Mean (cm)	95% CI		Change to preop (%)	P
≥−6.00 D	VisuMax	5.9	4.9	6.9	0.434	3.5	2.4	4.6	−40.7	0.335	4.0	2.8	5.1	−32.3	0.468
	IntraLase	5.7	4.5	7.0		3.8	2.4	5.1	−34.3		3.2	1.8	4.6	−43.6
	Eyes (n)	24				21					18
<−6.00 D	VisuMax	5.9	5.5	6.3	0.086	5.3	4.9	5.8	−9.7	0.095	5.2	4.7	5.6	−12.5	0.107
	IntraLase	5.8	5.3	6.3		4.8	4.3	5.3	−17.1		4.9	4.4	5.4	−14.8
	Eyes (n)	63				55					54

Notes: Estimated mean of corneal sensitivity, lower and upper bound of 95% confidence interval. VisuMax (Carl Zeiss Meditec, Jena, Germany) and IntraLase™ (Abbott Medical Optics Inc, Santa Ana, CA, USA).

Abbreviations: LASIK, laser in situ keratomileusis; CI, confidence interval.

Table 3 Reduction of TBUT following VisuMax and IntraLase™ LASIK

Preop						1 week					1 month					3 months
Level of myopia	Flap creation	Mean (sec)	95% CI		P	Mean (sec)	95% CI		Change to preop (%)	P	Mean (sec)	95% CI		Change to preop (%)	P	Mean (sec)	95% CI		Change to preop (%)	P
≥−6.00 D	VisuMax	10.1	8.8	11.4	0.318	8.3	5.8	10.9	−17.4	–	8.6	6.9	10.3	−14.8	–	10.2	8.6	11.9	+1.4	–
	IntraLase	9.5	7.9	11.1		5.3	2.3	8.3	−44.1		7.5	5.6	9.4	−20.8		8.2	5.9	10.4	−14.2
	Eyes (n)	25				5					13					13
<−6.00 D	VisuMax	10.5	9.1	11.9	0.377	8.8	6.5	11.0	−16.6	0.211	9.3	7.5	11.1	−11.6	0.981	8.8	7.0	10.6	−16.8	0.892
	IntraLase	10.2	8.9	11.4		7.5	5.9	9.2	−25.9		8.4	6.9	9.8	−17.7		8.0	6.6	9.5	−21.0
	Eyes (n)	62				19					33					36

Notes: Estimated mean of TBUT, lower and upper bound of 95% confidence interval. A statistical comparison using the linear mixed model adjusted for surgeon, age, and gender could not be performed for a level of myopia greater than −6.00 D due to small sample size.

Abbreviations: TBUT, tear film break up time; LASIK, laser in situ keratomileusis; CI, confidence interval; D, diopter.

Table 4 Reduction of Schirmer’s value following VisuMax and IntraLase™ LASIK

Preop						1 week					1 month					3 months
Level of myopia	Flap creation	Mean (cm)	95% CI		P	Mean (cm)	95% CI		Change to preop (%)	P	Mean (cm)	95% CI		Change to preop (%)	P	Mean (cm)	95% CI		Change to preop (%)	P
≥−6.00 D	VisuMax	11.3	7.6	15.0	0.577	8.8	5.1	12.5	−22.1	0.542	10.4	6.6	14.2	−7.8	0.464	10.1	6.1	14.1	−10.5	0.447
	IntraLase	11.7	6.6	16.9		9.2	3.9	14.5	−21.6		12.4	7.1	17.7	+5.8		9.4	3.9	14.8	−20.2
	Eyes (n)	24				22					21					18
<−6.00 D	VisuMax	15.2	12.2	18.3	0.316	12.4	9.4	15.3	−18.8	0.233	12.8	9.7	15.9	−16.0	0.956	12.7	9.5	15.9	−16.3	0.069
	IntraLase	13.7	11.0	16.4		10.7	8.0	13.4	−21.9		12.4	9.7	15.2	−9.0		13.7	10.9	16.6	+0.4
	Eyes (n)	62				62					57					51

Notes: Estimated mean of Schirmer’s, lower and upper bound of 95% confidence interval. VisuMax (Carl Zeiss Meditec, Jena, Germany) and IntraLase™ (Abbott Medical Optics Inc, Santa Ana, CA, USA).

Abbreviations: LASIK, laser in situ keratomileusis; CI, confidence interval; D, diopter.

Table 5 Changes over time in corneal fluorescein staining and incidence rates following VisuMax or IntraLase™ LASIK

Preop					1 week			1 month			3 months
Level of myopia	Flap creation	Mean	SE	Incidence rate (%)	Mean	SE	Incidence rate (%)	Mean	SE	Incidence rate (%)	Mean	SE	Incidence rate (%)
≥−6.00 D	VisuMax	0.0	0.0	0	0.5	0.3	38.5	0.4	0.2	30.8	0.3	0.2	18.2
	IntraLase	0.1	0.1	8.3	0.6	0.3	16.7	0.3	0.2	25.0	0.2	0.2	20.0
	Eyes (n)	25			25			25			21
<−6.00 D	VisuMax	0.0	0.0	3.2	0.7	0.2	35.5	0.1	0.1	6.5	0.2	0.1	21.4
	IntraLase	0.0	0.0	0	0.9	0.2	46.9	0.2	0.1	15.6	0.3	0.1	13.8
	Eyes (n)	65			65			65			57

Notes: Estimated mean of corneal staining score ± standard error. VisuMax (Carl Zeiss Meditec, Jena, Germany) and IntraLase™ (Abbott Medical Optics Inc, Santa Ana, CA, USA).

Abbreviations: LASIK, laser in situ keratomileusis; SE, standard error; D, diopter.