Real-Time Microscope-Integrated OCT to Improve Visualization in DSAEK for Advanced Bullous Keratopathy

Abstract

Purpose: To report the intraoperative use of microscope-integrated optical coherence tomography (MIOCT) to enable visualization for Descemet's stripping automated endothelial keratoplasty (DSAEK) in 2 patients with advanced bullous keratopathy.

Methods: Patient 1 was an 83-year-old female and patient 2 was a 28-year-old male both with limited vision and significant pain from bullous keratopathy who underwent palliative DSAEK. Because of the severity and chronicity of the corneal decompensation in both patients, the view past the anterior cornea was negligible using standard microscope illumination techniques. We used spectral-domain (Patient 1) and swept-source (Patient 2) MIOCT, both of which rely on infrared illumination, to visualize key parts of the DSAEK procedure.

Results: Graft insertion, unfolding, tamponade, and attachment could be dynamically visualized intraoperatively despite the nearly opaque nature of the host corneas. Postoperatively, the grafts remained attached with significant corneal clearing, and there was improvement in visual acuity, and pain relief for both patients.

Conclusions: MIOCT is a valuable tool for the corneal surgeon, allowing for DSAEK to be successfully performed even when the surgical microscope view is limited from severe corneal edema, as is often the case in patients with advanced bullous keratopathy. By using MIOCT, these patients can benefit from the advantages of DSAEK despite a clinically opaque cornea, which would otherwise be treated with a penetrating keratoplasty.

Trial registration: ClinicalTrials.gov NCT01588041.

FIGURE 1. Spectral-domain microscope-integrated optical coherence tomography (SD-MIOCT) 2D B-scan images (left) and surgical microscope images (right) during DSAEK for severe bullous keratopathy in Patient 1

Visualization of the anterior chamber (AC) is difficult in all of the surgical microscope images on the right due to severe corneal edema. A, Preoperative images showing severely edematous cornea. In the MIOCT image on the left, the edematous cornea nearly fills the entire 1.5 mm depth range of this system. B, Images following graft insertion showing a large fluid interface between the graft and host cornea in the MIOCT image. Note that the cornea is artifactually folded over at the top of the image because the depth range was exceeded. The inserted graft is not visible in the microscope image on the right. C, Air tamponade images showing minimal fluid interface between the graft and host cornea on MIOCT. Notice the air reflection under the graft in the SD-MIOCT image. With the presence of the air tamponade, the graft edges are now visible in the microscope view as well. D, Conclusion of the case confirming minimal fluid interface between the graft and host cornea. (In all SD-MIOCT images, the red scale bar measures 1 mm laterally and the blue scale bar measures 1 mm axially.)

FIGURE 2. Swept-source microscope-integrated optical coherence tomography (SS-MIOCT) 3D volume images (left) with white boxes marking the corresponding 2D B-scan images (center) and surgical microscope images (right) during DSAEK for advanced bullous keratopathy in Patient 2

Visualization of the anterior chamber (AC) is difficult in all of the surgical microscope images on the right due to advanced corneal edema. A, Preoperative images showing advanced corneal edema with epithelial irregularity. B, Images after graft insertion showing the relative position of the unfolded graft to the host cornea in the MIOCT images. The presence of the graft is not visible in the microscope view on the right. C, Images following air tamponade showing residual fluid interface between the graft and host cornea in the MIOCT images. In the standard microscope view, the graft edges are now visible with the air tamponade but no information about the presence of the interface fluid is available in this view. D, Images following an anterior corneal venting incision showing a reduction in the fluid interface between the graft and host cornea. E, Images following partial BSS-air exchange confirming good graft-host apposition at the conclusion of the case. (In all SS-MIOCT images, the red scale bar measures 1 mm laterally and the blue scale bar measures 1 mm axially.)