Femtosecond Corneal Lenticule Extraction Compared With Conventional LASIK in Refractive Surgery
Narrative Responses:
Purpose
Comparative estimation of corneal flap forming with Moria microkeratome and VisuMax femtosecond laser including flap thickness, refraction, visual acuity, changes of contrast sensitivity and higher order aberrations after LASIK and FLEx operations for myopia and myopic astigmatism.
Methods
Two groups were enrolled, 70 eyes in each. Standard LASIK was performed in Group 1 and FLEx in Group 2. In both groups before and in 1 month after surgery wavefront aberrations were measured in Malacara notation with WASCA aberrometer (Carl Zeiss Meditec). Flap thickness at the corneal center and 1, 2, and 3 mm from the center was measured in both groups with Visante OCT (Carl Zeiss Meditec) in High Resolution Corneal Quad and High Resolution Corneal Single modes. Contrast sensitivity was measured in both groups with CSV-1000 unit (VECTORVISION). Follow-up was 1 month.
Results
In Groups 1 and 2, UCVA was 0.05; 0.06 before and 0.99 and 0.95 after surgery (p > 0.05). SE: -4.13 D; -3.78 D before and 0.02 D; 0.03 D after surgery (p > 0.05). BCVA: 0.98; 0.99 before and 0.99; 0.98 after surgery (p > 0.05). RMSHO: 0.18 µm; 0.17 µm before and 0.37 µm; 0.29 µm after surgery (p < 0.05). Spherical aberration: -0.12 µm; -0.11 µm before, -0.53 ± 0.30 µm; -0.24 ± 0.28 µm after surgery (p > 0.05). Flap thickness was irregular in Group 1 and regular in Group 2. Contrast sensitivity has returned to preoperative level within follow-up period.
Conclusion
VisuMax femtosecond laser gives a possibility to perform FLEX operations without excimer laser. VisuMax femtosecond laser creates corneal flaps with exactly preset thickness parameters unlike mechanical microkeratome. FLEX operation provides visual acuity up to best corrected preoperative level with restoration of contrast sensitivity under mesopic conditions by 1 month postop.