Glenn C. Yiu, MD, PhD: Impressions & Applications for Intraoperative OCT

September 15, 2016, EYE on the Future What's New

Surgeon experiences and impressions are very impactful when highlighting new technology or surgical techniques. Glenn C. Yiu, MD, PhD and his colleagues Drs. Justis P. Ehlers, Sunil Srivastava, Jay Stewart and Ruwan Silva participated in a recent symposium at the American Society of Retina Specialists, ASRS, in San Francisco. RetinaLink spoke to Dr. Yiu to seek his perspective on what he liked best at this program featuring ZEISS’ RESCAN® 700. Dr. Yiu is on the faculty at the University of California, Davis Health System in Sacramento, CA.

Yiu 2014 - Suit
Glenn C. Yiu, MD, PhD

RetinaLink (RL): Discuss your impressions of ZEISS’ ASRS symposium in San Francisco.
Glenn C. Yiu, MD, PhD (GY): The symposium at the American Society of Retina Specialists, ASRS, in San Francisco, was a great success. Yes, I was on the faculty but, I believe the success of the event was a direct result of providing new users to intraopertive OCT (iOCT) technology a venue to discuss their experiences and share their clinical pearls. With the availability of the first commercial iOCT system by ZEISS, it was very valuable to have an opportunity for early adopters to communicate with their peers. This event gave us the unique opportunity to share our experiences together. The discussions and dialogue not only enhances our use of the device, but also provides feedback to the manufacturer for future iterations of the technology.

RL: What were the two key takeaways for the audience?
GY: I think the major theme of the symposium is that the RESCAN iOCT device has many more applications than originally imagined. At the beginning, I anticipated that iOCT will be mostly useful for macular surgery, especially in membrane peeling cases where iOCT helps to identify any residual tissue. However, there are many unanticipated instances where iOCT came in handy as well. During retinal detachment surgeries, areas of questionable residual subretinal fluid can be confirmed by iOCT. One of my colleagues used iOCT to measure the wound depth of a scleral window for uveal effusion. You may be thinking, “why would I need this device?” Often times, a person won’t recognize how useful a tool can be until you actually have it. Once I started using iOCT in surgery, I continue to find new uses with every case.

Another major theme was how differently different surgeons employ the technology. Some surgeons like to use heads-up display inside the eyepiece to give live feedback during complex dissections in retinal surgery, while others prefer to pause surgery to look at the external display which has a higher quality image. Also, some surgeons prefer the 5-line display mode with simultaneous scanning of 5-horizontal lines, while others use a 2-line display with a vertical and a horizontal line scans. The method of visualization varies between surgeons and between the types of surgeries being performed.

RL: Has Intraoperative OCT caused you to change your treatment plan or assisted you with an unforeseen complications during surgery?
GY: The short answer is yes. Before the advent of iOCT, surgeons made many intraoperative decisions based on clinical appearance, which can be somewhat misleading. iOCT removes a lot of the uncertainy when the clinical appearance is not clear. Whether there is a small amount of residual epiretinal membrane, an iatrogenic macular hole, or incompletely drained subretinal fluid; iOCT technology improves the certainty and can improve clinical judgment during surgery.

RL: Has the ZEISS RESCAN changed your surgical workflow?
GY: Many people worry that using iOCT can negatively impact surgical workflow. However, the ReScan system is fast and easy to activate during surgery. It takes less than a minute to quickly scan an area of suspicion, and can even potentially save you many minutes of unnecessary surgical maneuvers. In Dr. Justis P. Ehlers’ study at the Cleveland Clinic, Cole Eye Institute, they found that iOCT can actually help retinal surgeons realize that there was no additional membrane to peel. Thus, investing a few seconds using iOCT to increase the anatomic information during surgery can actually save me time in the long run.

RL: How does RESCAN affect your Fellows or younger surgeons and their learning curve?
GY: Retinal fellows who train with iOCT are very lucky to have this level of information feedback during their training. They do not have the clinical experience to always understand what they are seeing in surgery. Turning on the iOCT allows the trainee to instantly and clearly see what the clinical appearance may correspond to anatomically. I think ReScan will heavily benefit surgical education.

RL: In your opinion, what cases is the RESCAN most useful for?
GY: The RESCAN 700 is useful for many pathologies. In my opinion, any macular surgery such as epiretinal membrane (ERM) peeling or internal limiting membrane (ILM) peeling benefit most from iOCT. Not only can it delineate the extent of a membrane, as with triamcinolone or indocyanine green (ICG) staining, it can also provide a sense of topography – identifying locations where membranes may be more elevated above the retina. This additional information cannot be obtained with membrane staining alone.

RL: Retina continues to be the focus of new drug delivery for retina pharmaceuticals and new innovation in medical devices. How will iOCT benefit retina specialists with these new developments?
GY: That is a great question and yes, iOCT will certainly be beneficial for these kinds of new innovations. There are retinal implants, stem cell transplantations, and gene therapy trials that require subretinal delivery of the device, cells or virus. Accessing the subretinal space with a thin cannula requires a high level of precision to ensure proper delivery. iOCT provides excellent real-time anatomic visualization that is ideally suited for these applications. At the ASRS meeting, Dr. Tamer Mahmoud presented cases of using free-flap retinal transplantation for closure of chronic large macula holes. I also think iOCT would be invaluable in these kinds of cases where the anatomy can be confirmed prior to completing the surgery.

So, in summary, I think that it’s always better to have more information. Intraoperative OCT allows retina specialists to have high-resolution anatomic visualization during surgery. The outlook is bright for surgical delivery of biologics or devices in the future, and iOCT technology will no doubt be critical in the armamentarium of the next generation of retinal surgeons.

Dr. Glenn Yiu can be reached via e-mail –

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