title: Efficacy of Intrastromal Corneal Ring Segments Combined With Flash Collagen Cross-Linking in Keratoconus.
abstract: OBJECTIVE
  To evaluate outcomes, efficacy, and safety of intrastromal corneal ring segment implantation for treatment of keratoconus combined with collagen cross-linking (CXL) with 1-year follow-up.
  
  
  METHODS
  One hundred nineteen eyes of 82 patients with keratoconus (37 females) underwent femtosecond (Intralase FS; Abbott Medical Optics, Inc) laser-assisted intrastromal corneal ring segment implantation (INTRASEG; Gamma Vision) with flash CXL (18 mW/cm for 5 minutes). The outcome measures were uncorrected distance visual acuity (UDVA), best-corrected distance visual acuity (CDVA), subjective refractive error, keratometry values, and corneal thickness.
  
  
  RESULTS
  Mean age of patients at implantation was 31 years (range 12-63, SD 9.5). According to the Amsler-Krumeich scale of keratoconus severity, 62 eyes were type 1 (52%), 43 eyes, type 2 (36%), and 14 eyes, type 3 (11.8%). Statistically significant improvement of UDVA/CDVA and reduction in the mean cylinder and mean keratometry at 1 year were observed. Mean UDVA (logMAR) was 1.11 ± 0.61 (SD) preoperatively and 0.54 ± 0.58 (SD) postoperatively (P < 0.001). Mean CDVA was 0.52 ± 0.18 (SD) preoperatively and was 0.14 ± 0.17 (P < 0.0001) postoperatively. Preoperative Kmax was 48.75 diopters (D) (range 41.0-55.0 D), and postoperative Kmax was 46.18 D (P < 0.0006); preoperative Kmin was 44.69 D (SD) 3.59 and postoperative Kmin was 43.00 D (SD) 2.53. The mean cylinder was -5.19 D preoperatively (range -0.80 to -8.80 D) and -2.6 D (range -1.00 to -7.25) postoperatively. Mean corneal pachymetry was 486.6 μm (range 391-591). No intraoperative complications occurred. No patient lost any lines of UDVA or CDVA.
  
  
  CONCLUSIONS
  Implantation of the INTRASEG with the Intralase combined with flash CXL was apparently safe and effective in treatment of keratoconus. The variety of options in thickness and arc length of the segments enables more precise correction of keratoconus and refractive errors.
authors.affiliation: Department of Corneal Disease, Instituto Zaldivar, Mendoza, Argentina.
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Gordillo
authors.forename: Juan C
authors.initials: JC
authors.lastname: Grandin
authors.forename: Roger
authors.initials: R
authors.lastname: Zaldivar
authors.forename: Roberto
authors.initials: R
authors.lastname: Zaldivar
authors.forename: Adriana C
authors.initials: AC
authors.lastname: Lotfi
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003094:Collagen / Q000378:metabolism*; D003131:Combined Modality Therapy; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000378:metabolism / Q000601:surgery*; D019781:Corneal Topography; D003432:Cross-Linking Reagents; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy / Q000378:metabolism / Q000601:surgery / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D019904:Polymethyl Methacrylate; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012256:Riboflavin / Q000627:therapeutic use*; D016896:Treatment Outcome; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D019904:Polymethyl Methacrylate; D012256:Riboflavin