J Korean Ophthalmol Soc.  2010 Mar;51(3):320-327.

Central Corneal Thickness Measured by Four Different Methods in Normal and Post-Femtosecond Laser-Assisted LASIK Eyes

• Park SH
• Choi SK
• Lee DH
• Kim JH

Abstract

PURPOSE
To compare corneal pachymetry assessment using four measurement methods in normal and post-femtosecond laserassisted LASIK eyes.
METHODS
Central corneal thickness was measured sequentially using Orbscan II, Pentacam, Galilei and ultrasonic pachymetry in 30 normal, non-surgical eyes (Group I), 30 eyes one to six months after femtosecond laser-assisted LASIK (Group II), and 30 eyes six months or longer after femtosecond laser-assisted LASIK (Group III).
RESULTS
In Group I, corneal thickness measurements were similar for all four methods (P=0.202, one way ANOVA). In Groups II and III, corneal thickness measurements were significantly different (P=0.000, respectively, one way ANOVA). Compared to the Pentacam, Galilei and ultrasonic pachymetry, Orbscan significantly underestimated the corneal thicknesses in Groups II and III (P<0.005, respectively, one way ANOVA).
CONCLUSIONS
Central corneal thicknesses of normal eyes were similar for all four measurements, therefore corneal thickness measurements before refractive surgery using all four measurements is suitable. However measurements obtained with the Orbscan II were thinner than those obtained with the Pentacam, Galilei or ultrasonic pachymetry in post femtosecond laserassisted LASIK eyes. Further studies are needed to determine which instrument is more accurate in measuring central corneal thickness before and after refractive surgery.

Keyword

Central corneal thickness; Femtosecond laser assisted LASIK; Galilei; Orbscan; Pentacam

MeSH Terms

Corneal Pachymetry
Eye
Keratomileusis, Laser In Situ
Refractive Surgical Procedures
Ultrasonics

Figure

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  Figure 1. Mean and 95% CI of CCT measurement by Orbscan, Pentacam, Galilei and US in Group I (CI=confidence interval; CCT=central.thickness; US=Ultrasonic pachymetry).

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  Figure 2. Mean and 95% CI of CCT Measurement by Orbscan, Pentacam, Galilei and US in Group II (CI= confidence interval; CCT=central. thickness; US= Ultrasonic pachymetry).

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  Figure 3. Mean and 95% CI of CCT Measurement by Orbscan, Pentacam, Galilei and US in Group III. (CI= confidence interval; CCT=central. thickness; US=Ultrasonic pachymetry).

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  Figure 4. Bland-Altman plots of Galilei, Pentacam and Orbscan CCT readings against US measurement in Group I. The middle line is the mean and the lines on the side represent the upper and lower 95% limits of agreement (LoA).

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  Figure 5. Bland-Altman plots of Galilei, Pentacam and Orbscan CCT readings against US measurement in Group II. The middle line is the mean and the lines on the side represent the upper and lower 95% limits of agreement (LoA).

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  Figure 6. Bland-Altman plots of Galilei, Pentacam and Orbscan CCT readings against US measurement in Group III. The middle line is the mean and the lines on the side represent the upper and lower 95% limits of agreement (LoA).

Reference

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