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Li Chen, Eugenia Thomas, Dimitri Chernyak; Assessment of corneal changes after LASIK myopia treatment using OCT and topography. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):3935.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the corneal changes of postoperative LASIK eyes after myopia treatments using corneal optical coherence tomography (OCT) images and corneal topography images.
This study included 58 eyes with preoperative MRSE ranging from -4.00D to -12.00D. All eyes were treated for moderate to high myopia with LASIK treatments using 8mm ablation zone with 6mm optical zone. Preoperative and postoperative images were taken from each eye with corneal OCT by RTVue CAM (Optovue Inc.), and corneal topography by iDesign Advanced WaveScan Studio (AMO Development, LLC). Preoperative and the 3-month postoperative corneal measurements were analyzed to assess the corneal changes after LASIK treatment. Wavefronts, corneal pachymetry maps and corneal surface profiles were evaluated in comparison to the desired treatments within 6mm optical zone. Corneal power and corneal curvature values were extracted from the central 3mm zone.
The ablation shapes obtained from the 3-month postoperative measurements were in close agreement with the targeted ablation shapes derived from preoperative wavefront exams. Compared to the preoperative corneal measurements, postoperative changes of corneal anterior surface were also consistent with the myopia treatments including decreased corneal power (P<0.001) and increased corneal curvatures (P<0.001). There was excellent correlation between the anterior topography difference maps from iDesign and pachymetric changes obtained from the OCT. No significant difference in the posterior corneal surface was observed between preoperative and postoperative measurements of mean corneal power (P=0.566) and mean curvature radius (P=0.473). On average, the 3-month postoperative corneal epithelium became thicker with increased 3 microns central epithelial thickness (P<0.001).
Corneal OCT images and corneal topography images from preoperative and postoperative measurements provide very useful information to evaluate corneal changes after LASIK treatment. This study shows that there is no significant change in the posterior power and posterior curvature radius after LASIK myopia treatment. After LASIK procedure, mean corneal epithelial thickness increased by 3 microns, which was statistically significant. Furthermore, the study shows close agreement between the two instruments on the measurement of the achieved ablation profile as well as agreement with programmed correction.
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