title: Intraoperative corneal thickness monitoring during corneal collagen cross-linking with isotonic riboflavin solution with and without dextran.
abstract: OBJECTIVE
  The aim of this study was to analyze and compare corneal thickness changes during corneal collagen cross-linking procedures performed with isoosmolar riboflavin solution with 20% dextran and without dextran in corneal ectatic diseases.
  
  
  METHODS
  The patients in this study were analyzed in 2 groups: group 1 receiving riboflavin solution containing 20% dextran and group 2 receiving dextran-free riboflavin solution. Corneal thickness measurements were obtained with ultrasonic pachymetry at 6 different time points: preoperatively and at 0, 15, 30, 45, and 60 minutes after epithelial removal and initiation of ultraviolet A irradiation.
  
  
  RESULTS
  Twenty-seven eyes of 27 patients with progressive keratoconus were included in the study. In group 1 (n = 13), the mean preoperative thinnest pachymetric readings were 469.3 ± 8.5 μm, which decreased to 423.8 ± 8.9 μm after deepithelization and further decreased to 385.9 ± 10.9 μm at 15 minutes. The corneal thickness assumed a steady course at the 30-, 45-, and 60-minute measurements (378.9 ± 9.8 μm, 384.5 ± 10.5 μm, and 396.7 ± 9.4 μm, respectively). The initial change was statistically significant (P < 0.01). In group 2 (n = 14), the corneal thickness decreased from 459.4 ± 3.8 μm to 414.7 ± 2.6 μm with deepithelization, after which it increased steadily with the initiation of the dextran-free riboflavin solution. The final measurement in group 2 was 474.1 ± 9.4 μm; the increase at each time point was statistically significant when compared with the previous measurement (P < 0.01).
  
  
  CONCLUSIONS
  Using isoosmolar riboflavin solution without dextran causes a steady increase in the corneal thickness during the cross-linking procedure, as opposed to riboflavin with dextran. This result might be beneficial in broadening the spectrum of cross-linking indications in patients with thin corneas.
authors.affiliation: *Department of Ophthalmology, Necmettin Erbakan University School of Medicine, Konya, Turkey; and †Biostatistics Unit, Department of Medical Education and Informatics, Necmettin Erbakan University School of Medicine, Konya, Turkey.
authors.forename: Refik
authors.initials: R
authors.lastname: Oltulu
authors.forename: Günhal
authors.initials: G
authors.lastname: Şatirtav
authors.forename: Meryem
authors.initials: M
authors.lastname: Donbaloğlu
authors.forename: Hürkan
authors.initials: H
authors.lastname: Kerimoğlu
authors.forename: Ahmet
authors.initials: A
authors.lastname: Özkağnici
authors.forename: Adnan
authors.initials: A
authors.lastname: Karaibrahimoğlu
mesh_terms: D000328:Adult; D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000473:pathology*; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D003911:Dextrans / Q000627:therapeutic use*; D004338:Drug Combinations; D006801:Humans; D007432:Intraoperative Period; D007552:Isotonic Solutions; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D009929:Organ Size; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012256:Riboflavin / Q000627:therapeutic use*; D014466:Ultraviolet Rays; D014792:Visual Acuity; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D003911:Dextrans; D004338:Drug Combinations; D007552:Isotonic Solutions; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin