Intraoperative Optical Coherence Tomography for Enhanced Depth Visualization in Deep Anterior Lamellar Keratoplasty From the PIONEER Study

Deep anterior lamellar keratoplasty (DALK) is a challenging procedure that often results in conversion to penetrating keratoplasty. Preservation of Descemet membrane (DM) relies on indirect visualization of surgical planes. We describe a technique for enhanced visualization of key steps in DALK with intraoperative optical coherence tomography.Using a microscope-mounted spectral domain optical coherence tomography system, high-resolution images of various steps were obtained.Specifically, images were obtained of the trephination depth and proximity of the cannula tract to DM. Other key steps such as air cannula placement, assessment of the DM position and integrity after attempted big-bubble delivery, and assessment of graft-host apposition were readily visualized. The presence of intrastromal emphysema after air injection decreased visualization of deeper structures.Intraoperative optical coherence tomography allows visualization of depth-dependent anatomy and changes from specific surgical interventions during DALK not appreciated with the en face operating microscope view and has the potential to facilitate big-bubble delivery. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT02423161.