We Can’t See Everything

Evidence is building that intraoperative OCT is useful for macular surgery. Before evaluating the role for OCT in the operating room, consider the perspectives on its clinical use when it first became available 20 years ago. Back then, some experts doubted the potential role for OCT in the management of ophthalmic diseases. In fact, many clinicians believed their own exam was superior, and asked questions like, “Is there any real use for this?” and “Is it just a cool new toy?”

Fast-forward to ophthalmic practice today: OCT drives diagnosis, therapeutic decision-making and disease surveillance more than any other imaging modality available. It’s superior to our own exams in many situations, including for the diagnosis of various pathologies, such as vitreomacular traction, epiretinal membranes, and myopic schisis. The opportunities for understanding anatomic relationships (such as the vitreoretinal interface) with OCT are outstanding. 

This technology that has already transformed the clinic is now beginning to make its mark in our operating rooms. Intraoperative OCT gives immediate feedback on the completion of surgical objectives, it allows visualization of translucent tissues and membranes, and it has the potential to improve clinical judgment, personalize care, and improve outcomes. The evidence is mounting – there are a growing number of published peer-reviewed papers which demonstrate the impact of intraoperative OCT on surgical decision-making (1)(2)(3)(4).

The PIONEER study, for example, looked at over 500 eyes, and in 15 percent of cases, intraoperative OCT actually altered surgical decision-making (2). How does this translate to outcomes? If we look at imaging-assisted epiretinal membrane (ERM) surgery without mandated internal limiting membrane (ILM) peeling, we see the recurrence rate is less than 1 percent. That’s comparable to rates achieved solely with ILM peeling in addition to ERM peeling.

Similar themes have been described with the DISCOVER study and others (1)(3)(4). In the DISCOVER study, in 16 percent of cases where surgeons felt they had completely peeled the membranes, occult residual membranes remained that required peeling. Conversely, in 20 percent of cases where surgeons believed there were residual membranes to peel, intraoperative OCT revealed that all membranes has been successfully removed. In these cases, intraoperative OCT prevented unnecessary additional surgical manipulations and improved efficiency. Overall, surgeons reported that intraoperative OCT impacted their surgical decision-making in over one-third of cases – for example, affecting their gas tamponade choice or reducing adjuvant dye use.

The early evidence suggests that – similar to the use of OCT in our clinics – although we would like to believe we can see everything, we can’t. When it comes to the question of intraoperative OCT in macular surgery, one of the real challenges is that it is impossible to know which cases will be impacted by the technology and which ones will not. Randomized clinical trials that assess long-term outcomes are still needed to further validate the specific role for intraoperative OCT in vitreoretinal surgery, and the planning for these studies is underway. Intraoperative OCT is an emerging and exciting technology that may provide a paradigm shift for surgical visualization and image-assisted vitreoretinal surgery.