title: Sequential Intracorneal Ring Segment Implantation and Corneal Transepithelial Collagen Cross-Linking in Keratoconus.
abstract: OBJECTIVE
  To assess the clinical outcomes after sequential surgical implantation of intracorneal ring segments and transepithelial corneal collagen cross-linking (TE-CXL) in keratoconic eyes.
  
  
  METHODS
  In this consecutive randomized study, 40 eyes of 29 patients with progressive mild to moderate keratoconus were included and were randomly divided into two groups. Group 1 included 20 eyes that underwent Keraring implantation, and group 2 included 20 eyes that underwent Keraring insertion followed by TE-CXL 1 month later. In both groups, channel creation was performed manually. Visual, refractive, and topographic outcomes were measured preoperatively and 1, 3, and 6 months postoperatively.
  
  
  RESULTS
  There was statistically significant improvement in both groups regarding uncorrected distance visual acuity (P < 0.001) and corrected distance visual acuity (P < 0.001), with a significant reduction in the refractive error and keratometric values (P < 0.001). There was no statistically significant difference between both groups regarding changes in uncorrected distance visual acuity, corrected distance visual acuity, and refractive error (P > 0.05). However, group 2 revealed a more statistically significant reduction in spherical refraction after 3 months (P = 0.04) and highly significant improvement after 6 months (P = 0.004).
  
  
  CONCLUSIONS
  Intracorneal ring segment implantation is an effective procedure for visual and refractive improvement in keratoconic eyes. The addition of TE-CXL to the procedure compensates for residual superficial irregularities, disrupts the progression of the disease, and provides greater improvements in spherical values. The process is simply a deep stretch with superficial lamellar stiffness.
authors.affiliation: *Research Institute of Ophthalmology, Research Institute of Ophthalmology, Cairo, Egypt; †Department of Ophthalmology, Beni-Suef University, Beni Suef, Egypt; and ‡Memorial Institute of Ophthalmology, Cairo, Egypt.
authors.forename: Hany S
authors.initials: HS
authors.lastname: Elsaftawy
authors.forename: Mansour Hassan
authors.initials: MH
authors.lastname: Ahmed
authors.forename: Mohamed Yasser Sayed
authors.initials: MY
authors.lastname: Saif
authors.forename: Rasha
authors.initials: R
authors.lastname: Mousa
mesh_terms: D000328:Adult; 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; D019573:Epithelium, Corneal / Q000187:drug effects; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D019904:Polymethyl Methacrylate; D011183:Postoperative Complications; D011446:Prospective Studies; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012030:Refractive Errors / Q000503:physiopathology; D012256:Riboflavin / Q000627:therapeutic use; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D019904:Polymethyl Methacrylate; D012256:Riboflavin