Abstract
Background and Objectives: Laser refractive surgeries such as LASIK are effective techniques to correct the refractive errors, but it increases the higher order aberrations and subsequently decreases visual quality. The aim of the present study was to evaluate changes of higher and lower order aberrations after LASIK in myopia and myopic astigmatism.
Materials and Methods: In this cross-sectional survey 100 eyes from 50 patients with myopia and myopic astigmatism were evaluated. Complete eye examinations were performed and best corrected visual acuity was determined in all patients preoperatively. Furthermore, ultrasonic pachymetry and topography linked aberrometry was performed. Higher and lower order aberrations (HOAS, LOAS) were measured. Uncomplicated LASIK was performed with Schwind ESIRIS system and at least 3 months after LASIK all parameters were recontrolled.
Results: Mean pre- and postoperative manifest refraction spherical equivalent (MRSE) was
-4.78±2.01 D and -0.34±0.20 D (P<0.001). Mean pre-LASIK total aberrations were 5.66±2.24µm that decreased to 1.47±0.67µm postoperatively. Following operation, focus and astigmatism (LOAS) decreased from -21.41±8.02µm and 4.34±3.24µm to -2.78±2.10µm and 2.48±1.53µm, respectively (P<0.001). Mean preoperative HOAS was 0.27 ±0.11µm that increased to 0.48±0.30µm postoperatively (P<0.001). This increase was correlated with amount of SE correction.
Conclusion: Conventional LASIK corrects myopia and myopic astigmatism and decreases total aberrations and LOAS, but increases HOAS that is positively correlated with the amount of attempted MRSE correction.