Setting Proper Expectations for Evaluating DAVS ~ Important Steps & Key Takeaways from Drs. Alan J. Franklin & David R. Chow

April 24, 2019, What's New

Everyone likes a good day with only a few surprises; however, your day shouldn’t be startling from start to finish especially in your operating room.

Evaluating new technology is mission critical to you and your patient. To ensure the best possible demonstration with visitors in your OR is to know all important requirements before your day to “test drive” in surgery.

Global retina meetings have had presenters over the last 24 months highlight, debate and discuss DAVS, Digitally Assisted Visualization Systems. It’s always a lively conversation… “My microscope is just fine, my head and neck never hurt seems to be a consistent comment and the status quo rebuttal is DAVS is life changing, my entire surgical team is involved in my surgical case and I can’t live without it to ensure LUXTERNA (voretigene neparvovec-rzyl, Spark Therapeutics, Philadelphia, PA) is injected properly in the subretinal space.”

Whatever your opinion may be on new technology from any corporate partner, setting proper expectations will ensure you have a better overall experience and ultimately decide whether you move forward with purchasing new technology and budgeting/investing for a capital expenditure.

RetinaLink contacted Alan J. Franklin, MD, PhD, who has been an early adopter of DAVS, and Dr. Franklin has reported changing his surgical plan based on 3D visualization. He outlined the importance of understanding the proper setup to ensure a proper surgical experience when you evaluate new technology.

Alan J. Franklin, MD, PhD

Dr. Franklin was very candid in his response about evaluating any technology, “You can play any round of golf with a mediocre set of golf clubs. On the contrary, if you are serious and competitive, you most likely will invest in blade performance club technology to have your best possible round, DAVS offers the same precision in retina surgery. Just as in golf, DAVS does require appropriate preparation to reap the full benefit of the technology.

Dr. Franklin continued by saying, “We are in a privileged sub-specialty where doctors can actively participate in research and development to directly benefit the patient. Look at how we determined AVASTIN® (bevacizumab) was successful for Wet-AMD. Dr. Phil Rosenfeld’s patient was undergoing chemotherapy treatment and their retina was dry. He then deduced the appropriate dose to give intravitreally, which gave our community quick access to this revolutionary technology. We enjoy this same privilege in terms of surgical technology development. Over the past decade, the retina community has benefitted and adopted microincision surgery with more precise instruments, higher cut rates, and better fluidics. We all know the importance of optimized visualization. Learning how to optimally visualize intraocular pathology is an important part of retinal surgical learning, and we all experienced as fellows that the view when our faculty operated was generally better compared to our visualization during training. It is only a natural evolution that we should gravitate towards more precise visualization to parallel the improvement in instrument precision. Stereopsis or depth of resolution is enhanced with DAVS, as well as dynamic range. Depth of field is also improved for surgeons over 40. In addition, the digital filters can improve contrast and visualization of retinal tissue through vitreous opacities such as blood.  Finally, the ability to see the retina machine settings in real time next to the surgical field allows us to closely monitor vacuum and flow so that vitreous and pre-retinal membranes can be more precisely removed over areas of retinal traction or detachment.  It’s analogous to flying a plane with instruments as opposed to simple line of sight. When all of these parameters are taken together, clearly DAVS produces better surgical visualization experience compared to standard analogue surgical visualization. In contrast to the years of preparation that it takes to master blade golf clubs, set up for DAVS to achieve all of the above benefits is relatively straightforward.”

David Chow, MD FRCS (C) Toronto, Canada has done an excellent job outlining the key parameters and benefits of proper DAVS setup. Dr. Chow emphasized, “It’s important to follow the basic steps in setup for NGENUITY® so that optimal visualization can be achieved.

David R. Chow, MD FRCS (C)

At the present time there are inconsistencies in opinion about the visualization achieved with the NGENUITY system. Our research has shown that to achieve optimal visualization the TV needs to be placed at 1.2 – 1.5 m, the camera aperture should be placed around 30% and maximal magnification should be used to maximize lateral and depth resolution when performing macular work. Interestingly, some surveys we have done show that at the present time only about 50% of surgeons are using the system with an optimal setup!” Dr. Chow added.

The photos below outline what you will experience if your setup is not optimal.
(Photos: Alan J. Franklin, MD, PhD)

Iris Just Right 

Iris Too Big

Iris Too Small

Monitor Too Far Away 

Important Steps & Key Takeaways Before Your DAVS Evaluation:

  1. Position the display monitor 1.2 – 1.5 m (4 ft.) below the patient’s feet.
    For example, if the patient is 5 feet tall then, the monitor should be placed at the patient’s knees.
  2. Set the camera aperture to 30% open.
  3. White balance light sources.
  4. Don’t use too much light, 20% for ALCON and for DORC light sources are sufficient.
  5. Do not Tilt to the Screen:
    Screen should not be tilted (key: not too far left or right and not too high or low). The surgeons eyes also need to be at the level of the center of the monitor. You have to able to see the retina while you operate.
  6. Parfoculize visualization. Zero microscope. Fine focus on optic nerve head with maximal magnification.
  7. Zoom in to fill the display
  8. For the initial 2-3 surgeries:
    — Choose a pseudophakic patient, if possible, for your first case.
    — If your patient has a light or dark eye, you may need to adjust the settings.

Dr. Alan Franklin can be reached via e-mail –

DISCLOSURES: President and CMO, RFE Pharma and Alcon Consultant.



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