Contralateral Eye Comparison Between Femtosecond Small Incision Intrastromal Lenticule Extraction at Depths of 100 and 160 μm.
OBJECTIVE
To compare the visual results, higher-order aberrations, and corneal biomechanical properties of femtosecond small incision lenticule extraction (SMILE) at depths of 100 and 160 μm.


METHODS
A prospective comparative interventional clinical trial of a series of patients who underwent SMILE. In the right eye, a refractive lenticule was created at a depth of 100 μm, and in the left eye, a depth of 160 μm was used. Manifest refraction, uncorrected visual acuity, total high-order aberrations (THOA), and corneal biomechanical properties of both eyes were evaluated 1 month postoperatively.


RESULTS
Thirty patients with bilaterally stable refractive errors were included in this study. One month postoperatively, mean corneal hysteresis was 9.71 ± 0.68 in the right eyes and 9.97 ± 0.77 in the left eyes, whereas the mean corneal resistant factor was 9.13 ± 1.04 and 9.31 ± 0.92 in the right and left eyes, respectively. Both corneal hysteresis and corneal resistant factor showed statistically significantly higher values in the left eyes (lenticule at a depth of 160 μm). No statistically significant differences were found between the right and the left eyes regarding manifest refraction, uncorrected visual acuity, and THOA.


CONCLUSIONS
Creating the refractive lenticule at a depth of 160 μm in SMILE had less effect on the corneal biomechanics than did creating a lenticule at a depth of 100 μm with no statistically significant differences in the refractive outcome and THOA between both groups.
Faculty of Medicine, Alexandria University, Egypt.
Ahmed Abd El-Kreem
AA
El-Massry
Mohamed Bahgat Badawi
MB
Goweida
Ahmed El-Sayed
Ael-S
Shama
Mohamed Hassan Elsayed
MH
Elkhawaga
Moones F
MF
Abdalla
D000328:Adult; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery*; D001696:Biomechanical Phenomena; D003315:Cornea / Q000502:physiology; D003319:Corneal Stroma / Q000601:surgery*; D048988:Corneal Surgery, Laser / Q000379:methods*; D057108:Corneal Wavefront Aberration / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008866:Microsurgery / Q000379:methods; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology; D013524:Surgical Flaps; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult