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Abstract
Purpose
To investigate the relationship among optical coherence tomography (OCT), ultrasound pachymetry, and Orbscan in central corneal thickness measurement and to evaluate the reproducibility of flap thickness using an IntraLase femtosecond laser.
Methods
Central corneal thickness was measured by OCT, ultrasound pachymetry, and Orbscan in 59 eyes of 30 patients before LASIK. After IntraLASIK, the corneal flap thickness measured using OCT was compared with the intended corneal flap thickness.
Results
Central corneal thickness measured by OCT was thinner than that measured by other instruments preoperatively, but there was no significant difference among these methods (p>0.01), and corneal thickness values obtained by ultrasound pachymetry and Orbscan correlated well with those obtained by OCT (r ranged from 0.804 to 0.889, p<0.01). After IntraLASIK, there was no significant difference between the mean measured flap thickness and the intended flap thickness (p>0.01).
Conclusions
OCT is a relatively accurate instrument for measuring corneal thickness and can easily measure the corneal flap thickness after LASIK. Compared with the results of a previous study, the mean measured flap thickness in this study was more reproducible with the IntraLase femtosecond laser.
References
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Figure 1.
Comparison of preoperative central corneal thickness.
There is no statistically significant difference among the three groups (p: 0.01).
Figure 2.
Scattergram showing the correlation between the preoperative central corneal thickness by ultrasound pachymetry and the preoperative central corneal thickness by OCT.
Figure 3.
Scattergram showing the correlation between the preoperative central corneal thickness by Orbscan II and the preoperative central corneal thickness by OCT.
Table 1.
Comparison of measured flap thickness at postoperative periods.
No statistical difference between measured and intended flaps (p>0.01)
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