Longitudinal comparison of femtosecond-assisted sub-Bowman keratomileusis versus photorefractive keratectomy for high myopia.
To longitudinally compare the visual and refractive outcomes and changes in corneal thickness between femtosecond-assisted sub-Bowmen keratomileusis (SBK) and photorefractive keratectomy (PRK) with mitomycin C in eyes with high myopia.



Patients with spherical equivalent ≥6 dioptres (D) who underwent femtosecond-assisted SBK or PRK with mitomycin C were recruited. All patients were examined preoperatively and after 1 week, and, 1, 3, 6 and 12 months postoperatively. Assessments included uncorrected and best-corrected distance visual acuity , and manifest refraction spherical equivalent. Corneal thickness was measured using swept source optical coherence tomography.



A total of 110 eyes were included (68 PRK, 42 SBK). Change in efficacy index and safety index was not significantly different between both groups beyond 1 week postoperatively (p≥0.116). Manifest refraction spherical equivalent changed significantly from -9.02±1.92 D preoperatively to -0.21±0.31 D and from -8.25±1.10 D preoperatively to -0.53±0.55 D at 1 year after PRK and SBK, respectively (p<0.0001). The variance of postoperative refraction was significantly smaller after PRK throughout the 1-year follow-up compared with SBK (p≤0.0024). The central corneal thickness stabilised at 1 week after PRK and 3 months after SBK.



Our study showed that femtosecond-assisted SBK and PRK with mitomycin C have comparable safety and efficacy for correction of high myopia. However, better predictability of postoperative refraction was noted after PRK compared with SBK.
Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong.|Hong Kong Eye Hospital, Kowloon, Hong Kong.
Tommy C Y
0000-0003-4228-9482
TCY
Chan
Department of Mathematics and Statistics, Hang Seng Management College, Hong Kong.
Marco C Y
MCY
Yu
University of Leeds School of Medicine, Leeds, UK.
Sammie
S
Mak
Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong.|Hong Kong Eye Hospital, Kowloon, Hong Kong.|Centre for Eye Research Australia, University of Melbourne, Victoria, Australia.
Vishal
V
Jhanji
D000328:Adult; D000704:Analysis of Variance; D003315:Cornea / Q000601:surgery; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016685:Mitomycin / Q000008:administration & dosage; D009216:Myopia / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000379:methods*; D012029:Refraction, Ocular; D014792:Visual Acuity; D055815:Young Adult
D016685:Mitomycin