title: Prospective Cohort Comparison of Visual Acuity and Contrast Sensitivity Between Femto Laser In Situ Keratomileusis and Orthokeratology for Low-to-Moderate Myopia.
abstract: OBJECTIVE
  To compare the visual acuity and contrast sensitivity (CS) after femto laser in situ keratomileusis (fLASIK) and orthokeratology (OK) in patients with low-to-moderate myopia.
  
  
  METHODS
  A total of 68 patients were enrolled in this prospective cohort study. Of these, 40 eyes from 40 patients with low-to-moderate myopia underwent fLASIK and 28 eyes from 28 patients underwent OK. In addition to uncorrected distance visual acuity and corrected distance visual acuity, photopic and mesopic CS (with CSV-1000E) were tested before treatment and at 1, 3, and 6 months after treatment.
  
  
  RESULTS
  The preoperative refraction and CS were not significantly different between the groups (P>0.05). Postoperative visual acuity and refraction were similar (P>0.05). The photopic CS of the fLASIK group was better than that of the OK group (P<0.01). The fLASIK mesopic CS was better than the OK at 3 c/d (P=0.023). In the fLASIK group, only the photopic CS of postoperative 12 c/d decreased at 1 month and 3 months (P<0.01) and 18 c/d decreased at 1 month (P=0.002); whereas in the OK group, all the postoperative photopic CS values decreased at 1 month (all P<0.01) and 3 months (P<0.05) and increased to the normal level at 6 months (P>0.05). While as to the mesopic CS, in the fLASIK group, the 3 c/d, 6 c/d, and 18 c/d decreased at 1 month (P<0.05) and in the OK group, the 3 c/d decreased at 1 month and 3 months (P<0.05) and the 6 c/d decreased at 3 months (P=0.041), and the 12 c/d and 18 c/d decreased at 1 month (P<0.01).
  
  
  CONCLUSIONS
  These results show that fLASIK provides better visual quality than OK for patients with low-to-moderate myopia.
authors.affiliation: Department of Ophthalmology (M.T., P.M., G.M.), Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China; and Department of Ophthalmology (M.T.), the First people's Hospital of Jining, Jining, Shandong, China.
authors.forename: Mingxia
authors.initials: M
authors.lastname: Tian
authors.forename: Ping
authors.initials: P
authors.lastname: Ma
authors.forename: Guoying
authors.initials: G
authors.lastname: Mu
mesh_terms: D000293:Adolescent; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000706:statistics & numerical data* / Q000627:therapeutic use; D008297:Male; D009216:Myopia / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D054158:Orthokeratologic Procedures / Q000379:methods*; D011446:Prospective Studies; D012029:Refraction, Ocular; D012720:Severity of Illness Index; D014792:Visual Acuity