Observation Of The Corneal Measured By OCT In Early Stage

OBJECTIVE:By observating the corneal thickness before LASIK and corneal flap thickness after LASIK measured by OCT to investigate the application of OCT in the assessment in early stage of corneal flap security.METHODS:Thirty-eight patients(76eyes) who have been performed LASIK are chosen in the experiment. Based on different spherical equivalents, the cases were divided into low and medium myopia group (44eyes,≤-6.00D), high myopia group (32eyes,>-6.00D). Then, the central corneal thickness before LASIK, corneal flap thickness after LASIK, corneal epithelial thickness before LASIK,1day and7days after LASIK are measured separately and we observate the changes of patients vision, then analyze the differences of preoperative corneal thickness between OCT and A-ultrasound; differences between120microkeratome settings and actual corneal flap thickness.RESULT:The measurement of preoperative central corneal thinckness obtained from OCT was lower than that from A-ultrasound, the difference is significant (P<0.05), and they have a good correlation, but there is no difference between different myopia groups. The central cornea flap thickness measured in the1st day by OCT (136.96±12.06μm) is less than the90microkeratome settings, the difference is significant (P<0.05). The central cornea flap thickness measured in the7th day by OCT(132.71±13.17μm) is less than the90microkeratome settings, and the difference between them is significant, but there was no difference between different myopia groups. Corneal epithelial thickness among different times are different, and the difference is significant (P＜0.05), but there is no difference between different myopia groups.CONCLUSION:1.OCT can be used as a reference for the corneal thickness measurement before LASIK, corneal flap and corneal epithelial thickness measurement in early stage after LASIK.2.The mean preoperative central corneal thinckness measured by OCT is lower than that from A-ultrasound, and the difference is significant.3.The mean of the Moria90microkeratome is higher than that default is different, but in this surgery we should estimate the depth of microkeratome cut accurately, so as to set aside more residual corneal stromal thickness.