title: Impression cytologic analysis after corneal cross-linking and insertion of corneal ring segments for keratoconus: two-year results.
abstract: OBJECTIVE
  To report the impression cytologic results after corneal cross-linking and insertion of intrastromal corneal ring segments for keratoconus.
  
  
  METHODS
  Thirty-nine eyes were distributed into two groups: 1) cross-linking group (patients underwent corneal cross-linking procedure), and 2) riboflavin eyedrops group (patients received 0.1% riboflavin (w/v) eyedrops in 20% dextran solution for 1 month). After 3 months, all patients underwent insertion of intrastromal corneal ring segments. Impression cytologic specimens were obtained from all eyes at baseline, at 1 month and 3 months after cross-linking or riboflavin eyedrops, and again at 6 months, 1 year, and 2 years after intrastromal corneal ring segment insertion.
  
  
  RESULTS
  Patients in the cross-linking group demonstrated improvement in the cell-to-cell contact of epithelial cells and the nucleus-to-cytoplasm ratio on the temporal conjunctiva after treatment (P=0.008 and P=0.047), respectively. On the superior conjunctiva, increases in goblet cell density (P=0.037) and level of organization of nuclear chromatin (P=0.010) after treatment were noted. Patients in the riboflavin eyedrops group demonstrated improvement in the cell-to-cell contact of epithelial cells on the superior conjunctiva after treatment (P=0.021). On the temporal conjunctiva, an improvement in the cell-to-cell contact of epithelial cells (P<0.001) and increases in the nucleus-to-cytoplasm ratio (P<0.001), goblet cell density (P=0.001), and less keratinization (P=0.011) were noted. No changes were identified on the cornea for either group. Fisher's exact test comparison of the impression cytologic total scores after treatment revealed no difference between groups.
  
  
  CONCLUSIONS
  Despite changes in some conjunctival parameters (e.g., cell-to-cell contact of epithelial cells, nucleus-to-cytoplasm ratio, level of organization of nuclear chromatin, goblet cell density, and keratinization), comparison of the total impression cytologic scores revealed no difference between groups.
authors: Department of Ophthalmology, Refractive Surgery Service, Universidade Federal de São Paulo - UNIFESP - São Paulo (SP), Brazil. adimararenesto@uol.com.br
authors: Adimara da Candelaria
authors: Ada C
authors: Renesto
authors: Jeison de Nadai
authors: Jde N
authors: Barros
authors: Mauro
authors: M
authors: Campos
mesh_terms: D000293:Adolescent; D000328:Adult; D003131:Combined Modality Therapy / Q000379:methods; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011446:Prospective Studies; D019919:Prosthesis Implantation / Q000379:methods*; D012256:Riboflavin / Q000627:therapeutic use*; D016896:Treatment Outcome; D014792:Visual Acuity; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D012256:Riboflavin