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What role does intraoperative OCT play in today’s surgery and in the future?
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Intraoperative OCT crucial in treatment of retinal disease
To the question “is intraoperative OCT necessary now or will it be necessary later,” my answer is definitely yes. We need OCT now because there is no better way of visualizing the vitreoretinal interface, of imaging an epiretinal membrane or the internal limiting membrane (ILM), and of exactly locating a macular hole and vitreomacular traction. It guides us through the delicate maneuvers associated with vitreoretinal procedures, such as membrane peeling and ILM peeling, including the identification of residual membranes, difficult to identify otherwise. Intraoperative OCT helps us limit the use of dyes and their potential adverse effects, still not entirely known and controversial.
We are going to need intraoperative OCT even more in the future because we are going to be injecting drugs in specific places. Stem cell therapy and gene therapy are soon to become part of our armamentarium and will require injections in precise locations within the retina. There is no way other than OCT to achieve that accuracy. So, I think that microscope-integrated OCTs are necessary now to improve our results and will become even more necessary in the future.
Pravin U. Dugel, MD, is an OSN Retina/Vitreous Board Member. Disclosure: Dugel reports he is a consultant for Alcon, Byeonics, Zeiss and Bausch Health.
Corneal surgery has little to gain from OCT
There is little that OCT can do to improve our performance as corneal surgeons. One advantage is to establish the residual stromal bed depth following anterior lamellar dissection. The only potential advantage in real time I can think of is to help locate the exact depth at which we inject air in anterior lamellar surgery. However, because cannulas are metallic, the signal is blocked, and we therefore cannot see how deep we are below the cannula. Perhaps in the future we could have plastic transparent cannulas, which may improve the view. Regardless, if we compare the image that we can see on the microscope while performing lamellar transplantation with the image provided by OCT, I wonder how many surgeons would actually choose to use the OCT to guide their surgical maneuvers.
One of the arguments intraoperative OCT users often focus on in their publications is that OCT guides decision-making during surgery and that in many instances — almost 50% — it is instrumental in modifying their decisions at some point. What cannot be demonstrated is whether by changing from the original plan they actually do anything better in terms of clinical outcomes. If OCT allows them to see that there is fluid in 40% of cases in the graft-host interface and this makes them change their approach to prevent postoperative detachment, it means that without the OCT they would have a 40% detachment rate, which does not correlate with the currently much lower rate of graft detachment of all surgeons, regardless of their experience. This means two things. Firstly that the level of fluid is likely to be clinically insignificant for the outcome. Secondly, OCT may prompt one to intervene and take unnecessary action, potentially detrimental for the final outcome. So in conclusion, for our surgery, intraoperative OCT is not worth the investment. There are many alternative options that can offer more success in leading our decisions.
Massimo Busin, MD, is from Villa Igea Hospital, Forlì, Italy. Disclosure: Busin reports no relevant financial disclosures.