Corneal thickness measurement using Orbscan, Pentacam, Galilei, and ultrasound in normal and post-femtosecond laser in situ keratomileusis eyes.
OBJECTIVE
To compare corneal pachymetry assessment using slit scanning imaging (Orbscan), rotating Scheimpflug imaging (Pentacam), dual Scheimpflug system (Galilei), and ultrasound pachymetry in normal and post-femtosecond (FS) laser in situ keratomileusis (LASIK) eyes.


METHODS
Sixty eyes of 60 patients were enrolled for this study, which consisted of 30 unoperated eyes (normal corneas) and 30 eyes after FS-LASIK (post-LASIK corneas). Central corneal thickness was measured sequentially using Orbscan II, Pentacam, Galilei, and ultrasound pachymetry, and the average value of measurements obtained by the 4 different methods were compared in each group.


RESULTS
In normal corneas, corneal thickness measurements were not different by all 4 methods [P = 0.202, 1-way analysis of variance (ANOVA)]. In post-LASIK corneas, the measurement was significantly different among those achieved by 4 methods (P < 0.001, 1-way ANOVA). Orbscan measurement was thinner than those yielded by Galilei, Pentacam, or ultrasound pachymetry with average of 47.7, 38.5, and 34.4 μm, respectively (all P values < 0.001, 1-way ANOVA and the Tukey multiple comparisons test) in post-LASIK corneas. Orbscan, Pentacam, and Galilei measurements showed good agreement with ultrasound pachymetry data in both groups, except Orbscan data in post-LASIK corneas showed a statistically significant difference from ultrasound pachymetry measurements (P value = 0.001, 1-way ANOVA and the Tukey multiple comparisons test).


CONCLUSIONS
Any of central corneal thicknesses obtained by all 4 measurement modalities might be acceptable before refractive surgery. However, in post-FS-LASIK eyes, measurements using Orbscan were thinner than those obtained with other modalities; in contrast, those with Pentacam or Galilei were comparable with ultrasound pachymetry.
Department of Ophthalmology, Ilsan Paik Hospital, Inje University, Kyunggi-do, South Korea.
Se-Hoon
SH
Park
Suk-Kyue
SK
Choi
Doh
D
Lee
Eun-Jung
EJ
Jun
Jin-Hyoung
JH
Kim
D000328:Adult; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography / Q000295:instrumentation; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D033401:Microscopy, Acoustic / Q000295:instrumentation; D009216:Myopia / Q000473:pathology / Q000601:surgery*; D009929:Organ Size; D010781:Photography / Q000295:instrumentation; D015203:Reproducibility of Results