title: Comparison of intrastromal corneal ring segment implantation only and in combination with collagen crosslinking for keratoconus.
abstract: OBJECTIVE
  To compare visual outcomes, corneal astigmatism, and keratometric readings in patients with progressive keratoconus undergoing intrastromal corneal ring implantation (ICRSI) only and in combination with ultraviolet A riboflavin mediated corneal collagen crosslinking (CXL).
  
  
  METHODS
  In this retrospective comparative study, there were 2 groups of keratoconus patients. Group 1 consisted of only ICRSI patients. Group 2 consisted of combined ICRSI-CXL patients. Preoperative and postoperative uncorrected distance visual acuity (UCDVA) and best-corrected distance visual acuity (BCDVA), spherical error, cylindrical error, and mean keratometry were compared.
  
  
  RESULTS
  The study evaluated 166 eyes of 121 patients with a mean age of 24.74 years. The UCDVA improved from 0.24 to 0.37 in group 1 and from 0.24 to 0.42 in group 2 at the last visit. The BCDVA improved from 0.34 to 0.62 in group 1 and from 0.31 to 0.67 in group 2. Spherical error decreased from -5.05 D to -1.65 D in group 1 and from -4.82 D to -1.52 D in group 2. Cylindrical error decreased from -6.06 D to -3.47 D in group 1 and from -5.66 D to -3.20 D in group 2. Mean keratometry values decreased from 51.89 D to 47.96 D in group 1 and from 50.89 D to 46.91 D in group 2. p Value was >0.05 in group comparisons. Ring explantation due to corneal melting was applied in 3 eyes.
  
  
  CONCLUSIONS
  Both combined ICRSI-CXL and ICRSI-only groups experienced favorable outcomes, without statistical difference in any studied effect of both treatment strategies.
authors.affiliation: Eye Clinic, Turkey Hospital, Istanbul, Turkey.
authors.forename: Hanefi
authors.initials: H
authors.lastname: Cakir
authors.forename: Gökhan
authors.initials: G
authors.lastname: Pekel
authors.forename: Irfan
authors.initials: I
authors.lastname: Perente
authors.forename: Selim
authors.initials: S
authors.lastname: Genç
mesh_terms: D000328:Adult; D003094:Collagen / Q000378:metabolism*; D003131:Combined Modality Therapy / Q000379:methods; D003319:Corneal Stroma / Q000378:metabolism / Q000601:surgery*; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000378:metabolism / Q000628:therapy*; D008297:Male; D017319:Photosensitizing Agents / Q000627:therapeutic use; D019919:Prosthesis Implantation; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D014466:Ultraviolet Rays; D014792:Visual Acuity; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin