Surprises of Corneal Epithelium After Refractive Surgeries
Purpose
To investigate the postoperative changes in the area of the epithelial layer in different parts of cornea and their impact on the results of ametropia laser correction.
Methods
The test group included 36 patients (72 eyes), with an average age of 25.5±0.77 years. Ametropia laser correction was performed on laser systems VisuMax® (Carl Zeiss Meditec AG, Germany) and the ALLEGRETTO Wave EYE-Q and WaveLight® EX 500 (Novartis/Alcon/WaveLight, Germany) according to the technology of LASIK in 10 eyes, FemtoLASIK in 32 eyes, Flex (Femtosecond Lentikule Extraction) in 18 eyes, SMILE (Small Incision Lentikule Extraction) in 12 eyes. During the research we used spectral OCT AVANTI RTVue XR (Optovue Inc, Fremont, California) with a nozzle for the study of the eye anterior segment.
Results
In myopia correction of low and average degree difference between postoperative values of the epithelium thickness in center of cornea and preoperative indicators was statistically insignificant. In the case of high myopia, these changes were statistically significant. Hyperactivity of epithelium depends on amount of laser ablation and has a lenticular shape. The opposite trend in the restructuring of epithelium were noted in patients after laser correction of complex hyperopic astigmatism: in the central corneal zone revealed a decrease in epithelium thickness in average 6.5±0,73 μm, in the ablation zone - epithelium hyperplasia was in average 8.8±0,85 μm
Conclusion
The study of the corneal epithelium by OCT after laser correction shows that in almost all cases in the postoperative period there are statistically significant changes in the corneal epithelium thickness, which strongly depends on the ablation volume and localization.