Quantitative analysis of Microdistortions in Bowman's Layer using optical coherence tomography after SMILE among different myopic corrections.
OBJECTIVE
To quantitatively analyze the characteristics of Bowman's layer microdistortions after femtosecond laser small incision lenticule extraction (SMILE) among different myopic corrections, and their correlations with stromal lenticule thickness.


METHODS
In this nonrandomized, prospective, controlled study, 63 eyes of 32 consecutive patients undergoing SMILE were divided into three groups according to the preoperative spherical equivalent (SE): greater than -6.00 D (20 eyes), -3.00 to -6.00 D (26 eyes), and -3.00 D or less (17 eyes). Measurement by slit-lamp microscope, uncorrected distance visual acuity (UDVA), manifest refraction, and Fourier-domain optical coherence tomography (FD-OCT) were conducted preoperatively and 1 day and 1 month postoperatively. Index M was calculated according to the OCT images to indicate the quantity of microdistortions in Bowman's layer.


RESULTS
Microdistortions in Bowman's layer were observed in 65.0% (13 of 20 eyes) and 30.8% (8 of 26 eyes) in the greater than -6.00 D and -3.00 to -6.00 D groups, respectively, 1 day postoperatively, and in 60% (12 of 20 eyes) and 23.1% (6 of 26 eyes) 1 month later. No Bowman's layer microdistortion was detected in the -3.00 D or less group postoperatively. The quantitative index M of microdistortions was higher in the greater than -6.00 D group than in the -3.00 to -6.00 D group at 1 day and 1 month (P < .05). There was no statistically significant difference between the indexes M on 1 day compared to 1 month. Index M was correlated with the preoperative SE and lenticule thickness (P < .05).


CONCLUSIONS
The incidence and range of microdistortions in Bowman's layer detected after SMILE are positively correlated with the myopic correction. High myopia tends to develop more microdistortions in Bowman's layer after SMILE.
Jie
J
Luo
Peijun
P
Yao
Meiyan
M
Li
Guichun
G
Xu
Jing
J
Zhao
Mi
M
Tian
Xingtao
X
Zhou
D000293:Adolescent; D000328:Adult; D050541:Bowman Membrane / Q000473:pathology*; D003316:Corneal Diseases / Q000175:diagnosis*; D003319:Corneal Stroma / Q000601:surgery*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D009216:Myopia / Q000601:surgery*; D011183:Postoperative Complications; D011446:Prospective Studies; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult