March 2020

IN FOCUS

Illuminating intraoperative technologies
Guidance systems: Available options and when they can help physicians


by Ellen Stodola Editorial Co-Director


ORA

IntelliAxis Refractive Capsulorhexis

CALLISTO

VERION
Source: Nicole Fram, MD

 

Nicole Fram, MD, Kendall Donaldson, MD, and Robert Weinstock, MD, discussed guidance systems and how they can help in clinical practice. They highlighted the different systems available and in which scenarios they’re best used.

How the available systems compare

The space has evolved quickly but also plateaued at the same time, Dr. Weinstock said. “Many of the technologies that were available a year or two ago have become more robust and refined with software updates and more utilization,” he said.
“Especially in today’s world of ‘high stakes’ cataract surgery and refractive cataract surgery where patients are paying extra to see without glasses, it’s good to have some device helping you achieve that goal,” he said.
While Dr. Weinstock said ORA (Alcon) may be considered the “gold standard,”
CALLISTO (Carl Zeiss Meditec) was introduced shortly after ORA and can help surgeons by feeding preoperative data into the operating room to guide surgery. It can tell the surgeon where to put a toric IOL or where to center a multifocal IOL. “That’s another type of guidance device, but it’s not as much about decision making,” he said.
Dr. Weinstock said that current guidance systems can be broken down into two categories: those that aid decision making and those that are more guidance driven.
Dr. Weinstock also discussed the concept of marrying preoperative devices and feeding them into the operating room, mentioning the VERION Image Guided System (Alcon),
which couples ORA and other Alcon systems, and the IntelliAxis system (LENSAR). The LENSAR system has moved from being a device that creates a capsulotomy, fragments the lens, and makes arcuate incisions on the cornea for astigmatism correction to being a device that can guide toric IOL placement very accurately, Dr. Weinstock said. He added that it can be used with several different preop corneal imaging devices such as the Marco 3D Wave, the Cassini (Cassini Technologies), and the
Pentacam (Oculus). These devices can wirelessly feed a corneal infrared image into the operating room, and once the laser docks onto the eye, it has an infrared camera. Using proprietary iris registration software, it can quickly compare the preoperative iris architecture to intraoperative iris architecture and do an alignment of the eye to adjust for cyclotorsion. “Now the laser will make the arcuate incision at the correct axis,” Dr. Weinstock said.
“It’s an evolving space for incorporating the femtosecond laser into intraoperative guidance, and that’s becoming part of the value of the femtosecond laser,” he said.
According to Dr. Fram, the most common commercially available intraoperative guidance systems are VERION, CALLISTO, and ORA. VERION and CALLISTO require an upright reference image whereas ORA does not, she said. In addition, the steep axis measurement of VERION and CALLISTO does not take magnitude or power of the astigmatism into account. “They are simply measurement for digital steep axis marking,” she said. “On the other hand, ORA will help with power, magnitude, and steep axis, as it is using intraoperative wavefront aberrometry and previous history to achieve these measurements.”
According to Dr. Donaldson, VERION is wonderful in principle because it helps create a plan for the patient that can be executed with the femtosecond laser and also helps the doctor to create a nomogram, which can increase accuracy long term. However, Dr. Donaldson noted there may still need to be some refinements of the system. “Alcon is working on trying to integrate some of the positives of the VERION system with the ORA system, and hopefully in the future all of that will be meshed together into one higher power intraoperative guidance system,” Dr. Donaldson said.

Automated vs. manual axis marking

Dr. Donaldson said she still marks all of her patients sitting up before starting her cases. “Any patient I’m doing astigmatism correction on, I still sit them up and mark them beforehand,” she said. “Many people don’t do that, but it makes me feel more confident.” Marking them beforehand allows her to make adjustments at the femtosecond laser, Dr. Donaldson said, adding that this is one scenario where ORA wouldn’t help. Dr. Donaldson uses both the LenSx (Alcon) and the Catalys (Johnson & Johnson Vision) femtosecond lasers, marks the patient sitting up beforehand, and uses rotational alignment to make sure the AK incisions are aligned properly. She added that one of the hopes for future lasers is to have the laser detect the steep axis and align the AK incisions automatically.
Dr. Fram noted that manual marking has been referred to as a “safety parachute” by Robert Osher, MD, in case the digital marking system fails intraoperatively. “Marking is most accurate at the slit lamp or with a level marker,” she said. “In addition, using a reference of iris or scleral vessels is very useful. When manual marking is free hand, there is risk of introducing inaccuracy.”

Are intraoperative guidance systems worth it?

Past ASCRS Clinical Surveys have shown that many surgeons think 10 degrees of rotation off axis for a toric IOL is acceptable, Dr. Fram said. This means the surgeon will lose 33% of effectivity. “The digital guidance systems allow surgeons to be more precise and deliver on the promise made to the patient,” she said. “In our practice, ORA took us from 83% to 92% on target for toric IOLs. We were able to look at our data and compare using the AnalyzOR [Alcon] to review actual outcomes.”
The IntelliAxis takes a reference image from a Cassini or Pentacam, loads it into the femtosecond laser, and creates tabs in the capsulotomy on the steep axis, Dr. Fram said. The IntelliAxis Refractive Capsulorhexis has biomechanically stable and permanent capsular marks that enable physicians to precisely mark the capsule on the steep axis to guide toric IOL alignment, both intraoperatively and postoperatively, Dr. Fram said. IntelliAxis-C steep axis corneal marking is also available.
All of these guidance systems allow you to stay on the axis and can provide more accuracy, Dr. Fram said. “However, the Barrett Toric Calculator remains the gold standard in determining magnitude of toric power,” she said.
Dr. Donaldson said ORA is especially helpful in post-corneal refractive surgery patients. She also likes to use ORA in patients who are highly myopic because there can be more errors with IOL calculations. Anytime there is a patient with an unusual eye, it helps refine the results, she added.
The CALLISTO, although it helps with alignment, doesn’t help with the post-refractive patients, Dr. Donaldson said, adding that she uses ORA on 40–50% of cases for either post-refractive or toric alignment reasons.
CALLISTO is the quickest device but helps mainly with toric alignment. “We would love to have an intraoperative guidance system integrated into the laser itself,” she added.
Cataract surgery used to be very task-based with not a lot of decision making, Dr. Weinstock said. “Now, it’s become more of a dynamic procedure where you’re thinking about things while you operate and potentially changing the plans,” he said. There are now more devices to learn from and understand as you have to make decisions in the operating room. These tools do have a learning curve. “But the more tools you have in your toolbox, the higher chance you have of delivering a good outcome for your patient,” Dr. Weinstock said.

At a glance

• Guidance systems are continually evolving and can be used both preoperatively and intraoperatively.
• Some guidance systems help the surgeon with decision making, while others are more guidance driven.
• Two of the major uses for guidance systems are helping with axis marking and toric IOL alignment.

About the doctors

Kendall Donaldson, MD
Bascom Palmer Eye Institute
Plantation, Florida

Nicole Fram, MD
Advanced Vision Care
Los Angeles, California

Robert Weinstock, MD
The Weinstock Laser Eye Center
Largo, Florida

Relevant disclosures

Donaldson
: Alcon, Johnson & Johnson Vision, Bausch + Lomb, Carl Zeiss Meditec
Fram: Alcon
Weinstock: Alcon, Johnson & Johnson Vision, Bausch + Lomb, Carl Zeiss Meditec, LENSAR

Contact

Donaldson: kdonaldson@med.miami.edu
Fram: nicfram@yahoo.com
Weinstock: rjweinstock@yahoo.com

Guidance systems: Available options and when they can help physicians Guidance systems: Available options and when they can help physicians
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