Microscope Integrated Intraoperative Optical Coherence Tomography-Guided DMEK in Corneas with Poor Visualization

Abstract

Purpose: To assess the utility of microscope-integrated intraoperative optical coherence tomography (Mi-OCT) for performing Descemet membrane endothelial keratoplasty (DMEK) in corneas with poor visualization.

Methods: It is a prospective interventional case series that included 25 consecutive cases of corneal decompensation with poor visualization that underwent Mi-OCT-guided DMEK at a tertiary eye care centre. The main outcome measures were graft attachment on day 3 and requirement for re-bubbling.

Results: The etiology for corneal decompensation was pseudophakic bullous keratopathy (n=17), Fuchs endothelial corneal dystrophy (n=4), failed graft (n=2), iridocorneal endothelial syndrome (n=1) and failed Descemet stripping automated endothelial keratoplasty (n=1). Complete graft attachment was noted in 72% of cases. Graft detachment was noted in 16% of cases which required re-bubbling. No intervention was done for shallow peripheral detachment (n=2) and peripheral Descemet membrane (DM) fold (n=1). All grafts were attached at six-months follow-up. The mean corrected distance visual acuity and central corneal thickness improved from 1.4 ± 0.5 logMAR and 799.6 ± 110.9 µm at baseline to 0.3 ± 0.3 logMAR and 536.28 ± 11.44 um at six months. Mi-OCT was helpful in visualizing areas of peripheral anterior synechiae, missing DM, retained DM tags after descemetorhexis, DMEK roll configuration and orientation in the injector and anterior chamber, interface fluid and peripheral folds in the DMEK graft.

Conclusion: Mi-OCT helps in identification of the anatomy and dynamics of the host DM, DM roll and anterior chamber in cases with poor visualization and is a useful tool while performing DMEK in such cases.

Keywords: DMEK; Mi-OCT; descemet membrane endothelial keratoplasty; iOCT; microscope-integrated intra-operative optical coherence tomography.

Figure 1

Intraoperative images of donor tissue preparation before trephining the peeled graft (A) showing fluid between the peeled DMEK graft and stromal bed on Mi-OCT; (B) showing the decrease in fluid space with the peeled DMEK graft falling back on the stromal bed after drying the edges with a Merocel wick on Mi-OCT.

Figure 2

Intraoperative images (A) showing retained DM tag (marked with red arrow) after descemetorhexis; (B) removal of a retained DM tag with intravitreal forceps.

Figure 3

Intraoperative image showing DMEK roll orientation in the DMEK injector (A) prior to injection (the graft is inverted with DM facing down as highlighted by the red arrow); (B) at the time of injection (the graft is oriented with the DM towards the right as highlighted by the red arrow).

Figure 4

Intraoperative images showing (A) tight scroll in anterior chamber; (B) double scroll with Descemet up and endothelium down (correct orientation); (C) double scroll with Descemet down and endothelium up (incorrect orientation); (D) well attached DMEK graft in a case of failed graft.

Figure 5

Intraoperative image showing (A) Fold at the edge of the graft with the DM folded down after injection of air; (B) injection of BSS below the graft at the site of fold to induce unfolding; (C) completely unfolded and attached graft.