title: Intrastromal corneal ring segment implantation for ectasia after refractive surgery.
abstract: OBJECTIVE
  To evaluate the clinical outcomes of intrastromal corneal ring segment (ICRS) implantation to correct ectasia in eyes with prior refractive surgery.
  
  
  METHODS
  Forty-one eyes of 25 patients (13 men, 12 women; mean age, 28.66 years) with ectasia after refractive surgery [photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK)] were included in a nonrandomized, retrospective, observational case series. Corneal tunnels were created by mechanical dissection in all eyes. Main outcome measures included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), refraction, keratometry, and computerized analysis of corneal topography. Patients were divided into two groups by the type of refractive surgery (Group A: PRK, Group B: LASIK).
  
  
  RESULTS
  The mean preoperative manifest astigmatism decreased from -1.88 to -0.84 D in Group A (p=0.096) and -3.18 to -1.77 D in Group B (p=0.000). The mean keratometric astigmatism decreased from -2.58 to -1.66 D in Group A (p=0.010) and -4.80 to -2.78 D in Group B (p=0.000). The mean spherical equivalent decreased from -2.97 to -2.05 D in Group A (p=0.065) and -3.31 to -2.42 D in Group B (p=0.014). No significant between-group differences were noted on the comparison of preoperative and postoperative results. No intraoperative or postoperative complications were observed.
  
  
  CONCLUSIONS
  ICRS implantation is a useful treatment option for ectasia following refractive surgery, and it has significantly reduced the refractive cylinder and increased best spectacle-corrected visual acuity.
authors.affiliation: Instituto de Olhos de Goiânia, Goiania, GO, BR.
authors.forename: Larissa Rossana Souza
authors.initials: LR
authors.lastname: Stival
authors.affiliation: Instituto de Olhos de Goiânia, Goiania, GO, BR.
authors.forename: Belquiz R do Amaral
authors.initials: BR
authors.lastname: Nassaralla
authors.affiliation: Instituto de Olhos de Goiânia, Goiania, GO, BR.
authors.forename: Marisa Novaes Falleiro Chaves de
authors.initials: MN
authors.lastname: Figueiredo
authors.affiliation: Hospital São Geraldo, Belo Horizonte, MG, BR.
authors.forename: Frederico
authors.initials: F
authors.lastname: Bicalho
authors.affiliation: Instituto de Olhos de Goiânia, Goiania, GO, BR.
authors.forename: João Jorge
authors.initials: JJ
authors.lastname: Nassaralla Junior
mesh_terms: D000328:Adult; D003316:Corneal Diseases / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D003319:Corneal Stroma / Q000601:surgery; D019781:Corneal Topography; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000209:etiology* / Q000601:surgery*; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D018903:Photorefractive Keratectomy / Q000009:adverse effects*; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult