Intraoperative OCT Pachymetry in Patients Undergoing Dextran-Free Riboflavin UVA Accelerated Corneal Collagen Crosslinking

ABSTRACT

Purpose: To assess intraoperative corneal pachymetry in patients undergoing accelerated corneal collagen crosslinking with a dextran-free riboflavin solution.

Methods: Prospective, non-comparative, multicenter interventional study. Thirty patients with progressive keratoconus were enrolled in the study from the Siena Crosslinking Center™ in Siena, Italy and the Eye Center in Catanzaro, Italy. The mean age was 26.9 ± 6.5 years. Patients underwent pulsed light accelerated crosslinking (PL-ACXL) by KXL I UV-A source (Avedro Inc., Waltham, MS, USA) with 8 min (1 s on/1 s off) of UV-A exposure, 30 mW/cm² and an energy dose of 7.2 J/cm². Corneal stroma was soaked with a dextran-free 0.1% riboflavin solution plus hydroxyl-propyl methylcellulose (HPMC) (VibeX Rapid, Avedro). Intraoperative corneal thickness was preoperatively (PRE-OP) evaluated by corneal optical coherence tomography (iVUE Optovue Inc., Fremont, CA, USA) after epithelium removal (EPI-R), after 10 min of riboflavin soaking (RS) and after UV-A irradiation (IR). Statistical analysis was conducted using a Wilcoxon test and SPSS v16.0. A p-value of <0.05 was considered to be statistically significant.

Results: Average PRE-OP central corneal thickness (CCT) and thinnest corneal thickness (TCT) were 437.3 ± 36.9 and 418.9 ± 28.8 μm, respectively. Average EPI-R CCT and TCT values were 388.5 ± 36.8 and 381.5 ± 36.61 μm, respectively. Average CCT and TCT values after 10 min RS were 385.2 ± 37.8 and 380.6 ± 36.7 μm, respectively. The final average CCT and TCT values after IR were 379.4 ± 37.2 and 378.1 ± 36.4 μm, respectively.

Conclusions: The study demonstrated a non-statistically significant intraoperative corneal thickness reduction in patients undergoing PL-ACXL corneal collagen crosslinking by using dextran free HPMC 0.1% riboflavin solution.

KEYWORDS:

• Collagen crosslinking
• cornea
• keratoconus
• OCT
• pachymetry

Acknowledgments

The authors thank Mrs. Jennifer Berkley for the manuscript’s editing.

Contributions to authors in each of these areas

1. Conception and design: C.M., R.M.

2. Analysis and interpretation: R.M., C.M., D.S.

3. Writing the article: R.M., C.M.

4. Critical revision of the article: C.M., R.M., D.S., R.M.

5. Final approval of the article: R.M., C.M., D.S, M.R, L.M, C.S., M.A.

6. Data Collection: R.M., C.M.

7. Provision of materials, patients, or resources: R.M., C.M.

8. Statistical expertise: C.S., M.A, L.M.

9. Obtaining funding: None

10. Literature search: M.A.

11. Administrative, technical, or logistic support: S.C.

Declaration of interests

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. The authors do not have any proprietary or financial interest in the devices and products described.