Microscope-Integrated OCT-Assisted Real-time Monitoring of Central Corneal Thickness During Corneal Cross-linking.

PURPOSE: To assess real-time intraoperative pachymetry changes occurring during corneal cross-linking (CXL) using microscope-integrated optical coherence tomography (Mi-OCT) and compare accuracy of various modalities of pachymetry assessment.

METHODS

This was a cross-sectional observational comparative study including 45 consecutive patients with progressive keratoconus planned for CXL. Mi-OCT (RESCAN 700) was used to measure central corneal thickness (CCT) during four stages of CXL: before epithelial debridement, after debridement, after riboflavin instillation, and after ultraviolet irradiation. Scheimpflug imaging, anterior segment OCT (AS-OCT), and ultrasound pachymetry were used to assess CCT preoperatively. All data were entered into Excel software (Microsoft Corporation) and analyzed.

RESULTS

The CCT significantly decreased after each step of CXL as measured on Mi-OCT (P < .0001). Mi-OCT overestimated the CCT significantly by 1.12 times on average (range: 1.02 to 1.43) compared to ultrasound pachymetry (P = .0004). CCT measured using Scheimpflug imaging and anterior segment OCT was statistically comparable to ultrasound pachymetry.

CONCLUSIONS

Mi-OCT provides a real-time assessment of CCT during CXL. However, because it overestimates the pachymetry, ultrasound pachymetry remains the gold standard for decision-making during CXL. [J Refract Surg. 2024;40(12):e934-e940.].