3-D heads-up displays have entered into many vitreoretinal surgery operating rooms in recent years.1 The current mainstream momentum of the system has been driven by the newly formed partnership between TrueVision and Alcon, with the system now being marketed as Ngenuity. Much has been written about 3-D heads-up retina surgery and its benefits, especially for macular surgery, and surgeons have shown that it is also well suited for complex cases such as tractional retinal detachment and trauma.2,3
Here, we explain why we use 3-D heads-up surgery for every retina case.
THE ERGONOMICS ISSUE
Retina surgeries can be particularly demanding, potentially requiring hours in the OR. Even with a good posture, retina surgeons may feel lumbar and/or cervical spinal strain after a long day loaded with challenging cases. Heads-up visualization displays allow surgeons to lean back and rest on the backrest of the chair and move their body more freely during surgeries, which is a great relief. These displays may ease musculoskeletal strain and may even, theoretically, prolong surgical careers.
During most cases, we set the light pipe intensity to about half of what we normally use under the conventional optical microscope. This is due to the digital amplification of the image signal that is possible with digital imaging systems. While it is difficult to measure associated outcomes of reducing retinal light exposure from the current standards, which are very safe in general, there may potentially be some benefit from decreasing the likelihood of light toxicity. This would be an interesting area for further investigation.
Reduced lighting requirements also allow for a smaller camera iris aperture, which can be manually adjusted during cases. A smaller iris aperture, combined with digital hyperstereopsis, can increase depth of field compared to conventional microscopes — which is particularly noticeable if the surgeon has decreasing accommodation amplitude.
This can be useful for many surgical maneuvers, including manipulation of complex pediatric tractional retinal detachments that may require simultaneous work at different anterior-posterior levels in the eye (See “Perfect for pediatrics,” page 13). Unlike conventional microscopy, the field of view remains stable when zooming in and spreads across the large screen. As a result, digitally assisted viewing systems often allow for greater panoramic views with simultaneous high magnification.
ANTERIOR MEMBRANE DISSECTIONS
We find the 3-D heads-up viewing system particularly useful for anterior membrane dissections, such as in stage 5 retinopathy of prematurity or familial exudative vitreoretinopathy, where meticulous dissections take place right below the pupillary plane under direct visualization (Figure 1, page 13).
Although the 3-D visualization systems are marketed for posterior-segment surgery, they provide fantastic anterior-segment views, where we find the hyperstereopsis to be more noticeable. In addition, sitting back with great immersive views during these longer, complex dissections makes for a pleasant experience.
TEACHING MADE MUCH EASIER
When we operate on retina cases at Massachusetts Eye and Ear and Boston Children’s Hospital, it is common to have medical students, residents and often international fellows and observers in the room to learn the surgical ins and outs. Not everyone can scrub in and use a side microscope, of course. Spectators would traditionally rely on the 2-D screen to watch the case, if one was available. However, the view on a small 2-D screen often does not replicate what the surgeons actually see through the microscope, causing much to be lost in translation when we educate our trainees.
3-D viewing systems offer a whole new level of immersive surgical education. For the first time, everyone in the operating room has exactly the same view. These systems also allow scrub nurses, anesthesia and other personnel to see exactly what the surgeon sees. This can motivate the team and may help them better anticipate your next steps, making for an overall smoother and more collaborative surgical experience (Figure 2, page 17).
CREATING SURGICAL VIDEOS
In the age of the Internet, surgical videos have become an important teaching tool. Videos can be downloaded and turned into either 3-D or 2-D videos, which are of beautiful quality and capture the benefits of the high dynamic range image processing. These video file sizes can be quite large, as you may imagine.
Videos can be shown on 3-D heads-up displays during case presentations or uploaded to several 3-D online platforms where they can reach a worldwide audience.
Perfect for pediatrics
Heads-up is invaluable for adult retina cases, but what about pediatric retina surgery? Are the nuances and complexities associated with pediatric retina surgery — which include needing optimal visualization to avoid iatrogenic breaks at all costs, altered optics, crowded anatomy due to smaller eyes and potentially longer cases — amenable to 3-D heads-up surgery? Here are some reasons digitally enhanced heads-up viewing systems may play a role in further advancing this specialized field.
- Pediatric retina surgeries may range from a very focused tissue transection to tedious membrane peeling that may take hours. Surgeons may appreciate the reduced musculoskeletal strain the ergomically friendly heads-up displays provide.
- The greater depth of field that heads-up systems afford can be particularly useful for manipulation of complex pediatric tractional retinal detachments that may require simultaneous work at different anterior-posterior levels in the eye.
- When we operate on pediatric retina cases at Massachusetts Eye and Ear and Boston Children’s Hospital, it is common to have many observers in the room to learn the surgical ins and outs, including international fellows from developing nations where pediatric retina surgeons are scarce. Because not everyone can scrub in and use a side microscope, spectators would traditionally rely on the 2-D screen to watch the case, if one was available. However, the view on the 2-D screen often does not replicate what the surgeons actually see through the microscope, so much was lost in translation when we educated our trainees. Thanks to the heads-up display, that is no longer the case.
- With pediatric surgery being a great unmet need in many developing and middle-income countries due to the surge in retinopathy of prematurity and lack of pediatric retinal surgeons,4 tele-education with surgical videos may improve how surgeons learn. Tele-education is already making inroads in training paradigms,5 and 3-D surgery may contribute if implemented effectively.
WORDS OF ADVICE
Any new technique or technology initially has a learning curve. Thankfully, for 3-D heads-up surgery, the learning curve is very short.
Most retina surgeons feel comfortable in the eye after a single or a few cases. The feeling of “something is different” lingers slightly longer for anterior-segment procedures such as suturing, because a negligible 0.07-second latency exists between surgical action and image display. This is not felt during the slower and fine movements in the posterior segment, but it may be slightly noticeable during larger and faster movements in the anterior segment, if one looked hard for it.
The most important pearl is not to forget about all the maneuvers that we unconsciously perform to optimize our view. Whether it’s moving the microscope when turning the eye, bringing the microscope lower to capture a larger field of view, keeping the cornea clear or keeping the optics focused, we may sometimes forget about the basics when a new instrument or viewing system is placed in front of us. Focusing, lighting, moving the eye and microscope together, and so on, all still are necessary.
3-D heads-up displays have arrived in vitreoretinal surgery rooms. Complex cases, including pediatric retina surgery are amenable and may benefit from the various advantages such as enhanced surgical training, improved ergonomics, wider depth of field and light exposure reduction. For us, the teaching and ergonomics are the most tangible.
The technology benefits both adult and pediatric cases. Future studies hopefully will examine the potential benefits in rigorous studies, including whether surgical outcomes are improved.
The current technology is only the beginning, and we look forward to continued developments and possibilities for digital image overlays, filters, incorporating endoscopes and intraoperative optical coherence tomography to further enhance our operating experience. OM
- Eckardt C, Paulo EB. Heads-up surgery for vitreoretinal procedures: An experimental and clinical study. Retina. 2016;36:137-147.
- Yonekawa Y, Thanos A, Abbey AM, Thomas BJ, Todorich B, et al. Hybrid 25- and 27-gauge vitrectomy for complex vitreoretinal surgery. Ophthalmic Surg Lasers Imaging Retina. 2016;47:352-355.
- Yonekawa Y, Thomas BJ, Hassan TS. New self-retaining sutureless cellulose flanged disposable contact viewing system for vitreoretinal surgery. Retina. 2015;35:834-837.
- Gilbert C. Retinopathy of prematurity: a global perspective of the epidemics, population of babies at risk and implications for control. Early Hum Dev. 2008;84:77-82.
- Chan RV, Paten SN, Ryan MC, Jonas KE, Ostmo S, et al. The Global Education Network for Retinopathy of Prematurity (Gen-ROP): Development, implementation, and evaluation of a novel tele-education system (An American Ophthalmological Society Thesis). Trans Am Ophthalmol Soc. 2015;113:T2.