An Overview of Intraoperative OCT-Assisted Lamellar Corneal Transplants: A Game Changer?

Abstract

Intraoperative optical coherence tomography (iOCT) is a noninvasive imaging technique that gives real-time dynamic feedback on surgical procedures. iOCT was first employed in vitreoretinal surgery, but successively served as a guidance in several anterior segment surgical approaches: keratoplasty, implantable Collamer lens (ICL) implantation, and cataract surgery. Among all of those approaches, the unbeatable features of iOCT are fully exploited in anterior and posterior lamellar keratoplasty, and the purpose of this review is to focus on the advantages and shortfalls of iOCT in these techniques, in order to assess whether this technology could be a real step forward. In deep anterior lamellar keratoplasty (DALK), iOCT is useful to evaluate the needle depth into the corneal stroma, the big bubble dissection plane, and residual stromal bed, thus aiding the standardization of the technique and the reduction of failures. In Descemet stripping automated endothelial keratoplasty (DSAEK), iOCT allowed for clear visibility of fluid at the graft/host interface, allowing for immediate rescue maneuvers and granting the best graft apposition. In Descemet membrane endothelial keratoplasty (DMEK), iOCT can track the lenticule unfolding in real time and assess graft orientation even in severe hazy corneas, thus optimizing surgical times, as well as avoiding the use of potentially hazardous exterior markers (such as the “S” stamp) and preventing unnecessary manipulation of the graft. Overall, the role of iOCT appeared crucial in several complicated cases, overcoming the difficulties of poor visualization in a fast, non-invasive way, thus raising this approach as possible gold standard for challenging conditions. Further improvements in the technology may enable autonomous centering and tracking, overcoming the current constraint of instrument-induced shadowing.

Cost‐effectiveness of the ADVISE trial: An intraoperative OCT protocol in DMEK surgery

“…This means variability in outcomes could potentially be less if a different setup was used. Second, the time horizon is 6 months postoperatively, which means long-term effects cannot be directly measured, although previous RCTs and real-world studies show little to no difference in graft survival between 6 and 12 months (Chamberlain et al, 2019;Dunker et al, 2020;Schlögl et al, 2016). For the cost variability, we report on the robustness present at 6 months using sensitivity analyses but expected costs after 6 months are not included.…”

“…Previously, we have observed that the utilization of iOCT in corneal surgery could increase clinical performance, increase the safety of DMEK surgery and aid in surgical decision‐making (Carlà et al, 2022; Cost et al, 2015; Dunker, Dickman, et al, 2021; Dunker, Veldman, et al, 2021; Pasricha et al, 2015; Sharma et al, 2020). Also, corneal transplantations are known to be cost‐effective, increase health utility and different transplantation techniques are compared before in cost‐effectiveness analyses (Beauchemin et al, 2010; Bose et al, 2013; Prabhu et al, 2013; Shah et al, 2021; Simons et al, 2019, 2022; van den Biggelaar et al, 2012).…”

iOCT-Assisted DSAEK Tamponade for Spontaneous Corneal Perforation with Secondary Bleb Formation in Pellucid Marginal Degeneration

“…Intraoperative optical coherence tomography (iOCT) is used extensively in complex anterior segment surgery, providing increased precision and thereby more safety and improved clinical outcomes. In lamellar keratoplasty, the successful application of iOCT has already been described 1 . For example, the iOCT can be used for defining the cutting depth of deep anterior lamellar keratoplasty (DALK) or for visualization of potential fluid in the interface in Descemet stripping automated endothelial keratoplasty (DSAEK) 2 , 3 , 4 .…”

“…Moreover, for the correct corneal graft positioning in Descemet membrane endothelial keratoplasty (DMEK), a marker was previously required. The iOCT allows recognition of the corneal graft orientation and further observation of the unfolding process of the graft without the need for marking [1,5].…”

Spontaneous Descemet Layer Dissection Without Pneumodissection in Femtosecond Laser-Assisted Mushroom-Type Deep Anterior Lamellar Keratoplasty

“…3,4 In addition, intraoperative anterior segment optical coherence tomography (AS-OCT) enables corneal visualization during DALK, offering real-time information for surgical planning and optical instrument localization which helps in reducing surgical complications and obtaining a more precise stromal dissection. 5…”