Abstract
Purpose
To compare central corneal thickness (CCT) measurements obtained using the Pentacam Scheimpflug system with those obtained using DGH ultrasound pachymetry (UP) in post-laser in situ keratomileusis (LASIK) eyes for myopia.
Methods
In a prospective study, measurement agreement was assessed in 143 eyes of 72 post-LASIK patients using both the Pentacam and UP at the Eye Consultants Center in Riyadh, Saudi Arabia.
Results
The mean CCT was 522±42.2 μm with the Oculus Pentacam and 516.2±40.6 μm with UP. The Bland-Altman plot showed that the mean ± SD for the differences between the 2 devices was 5.8±13.6 μm, with 95% confidence interval limits ranging from −20.9 μm to 32.6 μm. A test of statistical significance indicated that the mean differences of 5.8±13.6 μm differed significantly from zero (p<0.001; Wilcoxon signed-rank test), thus indicating that the Pentacam measurements tended to overestimate CCT compared with UP. Analysis of regression showed a high correlation between the values obtained with both devices (r=0.947, p<0.001).
Conclusions
In post-LASIK myopic eyes, although a high correlation has been shown between Pentacam and UP measurements, Pentacam tends to overestimate CCT compared to UP. Pentacam probably cannot be used interchangeably with UP in post-LASIK eyes for myopia.
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