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Practicing cataract surgery on a simulator
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John A. Hovanesian, MD, FACS: I am joined by Dr. Daniel Steen, the Vice Chairman of Operations of the Department of Ophthalmology at the Henry Ford Health System in Detroit.
We are talking about the Eyesi cataract and vitrectomy simulator system (VR Magic Technology Group), which has been in use in Dr. Steen’s department for a number of months for training residents in assessing their skills. Dr. Steen, tell us about the system.
Daniel W. Steen, MD: We have had the system for almost 1.5 years now, and it allows residents just starting out to develop the manual dexterity that is necessary to do cataract surgery. One additional bonus that we discovered is that residents who have actually done cataract surgery, if they are struggling on a certain part, will go back to the system, work on that particular part of the surgery, work through their problems and then go back and do it again.
Dr. Hovanesian: You have done thousands of cataract surgeries through the years prior to ever laying hands on the system. How real is it?
Dr. Steen: It is very good. It is not perfect, but it is very good. When I sat down and I had to figure out how I was going to have the residents use it, I read the instructions, which were written by non-ophthalmologists, and I tried to do it. Within three tries, I could get on all of the modules; I could get up into the 90s, and I figured that is pretty good. Then I took a first-year medical student and let them try. After three tries, they still had not gotten above the zero level, so I thought there was a very good translation from knowing how to do surgery and using the machine. The proof of going from the machine to having them do surgery was harder to demonstrate.
Dr. Hovanesian: How did that work? Do you require beginning surgeons to demonstrate skill on this before the operating room?
Dr. Steen: First-year residents are required to go through a series of modules that I set up. They are required to hit 80% on every one of the modules that I have set up somewhat arbitrarily. And then when they get to that level, when they start going to do their first cases, they have to have passed everything on the simulator. What I have noticed is that when they go in there, while they still may not know exactly how to do cataract surgery because it is not exact, they can move their hands. They can do simple things like focus the microscope properly, and they are actually in focus on the capsule. They can grab a capsule correctly, move it around in a circle. Maybe their size is not perfect, but they can then take direction and I can spend time on the things you can only do in the eye and not spend time on things you can do someplace else.
Dr. Hovanesian: Within cataract surgery itself, give us an example of some of the sections that you break down for surgeries, such as capsulorrhexis.
Dr. Steen: The unit itself has a number of things to allow you to use your hands. It has what they call a navigation module and anti-tremor module. You have them do those first so they can just move instruments inside the anterior chamber. And in the beginning, just holding your hand still, they will try it. Then I can spend the first 2 hours that they work on this with them one-on-one or one-on-two so they can learn how to position their hands properly on the head, how they can position themselves so they are sitting up straight and everything is at the right height.
They go through those modules and get better. The first one that really is like doing cataract surgery is the capsulorrhexis, and that turned out to be one of the strongest points. They can make a capsulorrhexis, and they can follow it around. If it goes outside or if they get a tear, it turns out that the physics that they have incorporated in their algorithms allows the “rescue maneuver” of backing up and pulling to the center to go right back to the center. So we can have them practice these things in a controlled simulation, get themselves into trouble and then come right back.
Dr. Hovanesian: Tell me what limitations, because it must have some, you run into in simulating surgery.
Dr. Steen: It is no substitute in tactile sensation. It does not allow you to put in sutures, so you still cannot give up your wet labs and your pig eyes or whatever other methods that you use. But the simulation for cataracts where you are actually having phaco, that is where it is weak. The company recognizes that, and it keeps working very hard at trying to come up with new things in that area. The texture of the cataract itself is more like Jell-O than it is a real cataract. It bounces around and does not split quite the same way, but it does allow you to use the foot pedal so you can use your right hand, left hand, right foot, left foot all together, so you can actually pull the quadrants into the center of the eye and then take them out.
Dr. Hovanesian: Where do you see the future taking this technology, and how do you see it fitting into your training program in the future?
Dr. Steen: We have always been using it as one part. It is not a replacement. Our idea of proper surgery for residents is to give them wet lab experience. After they have gone through a series of that concurrently, we do the simulator. As they get better at the simulator, then they are with us and they get their apprenticeship with direct supervision.
I think our simulating system will continue to allow them to progress more quickly. I have noticed that the residents who spend a lot of time on it, when they are down in the operating room for the first time, they can do things that residents who have not spent as much time cannot do. Now I cannot tell you for sure that they did not have more natural motivation and skill to begin with, but my impression is, having watched them at different levels, that it is the simulator that has made them better surgeons.
Dr. Hovanesian: Certainly to begin with, they are better surgeons for having tried it. I tried it myself on a recent visit to your institution and was very impressed, despite its limitations, with how real it was. And it seems to me that one day it might be used as a metric for who really should be guided toward intraocular surgery and who might be guided in other directions. Do you think that is a reality that could come?
Dr. Steen: I think that is a distinct possibility. I think that first it will have to simulate the true cataract extraction better, and you can take people who are average and make them much better than average. I think that will be its first step, rather than using it as a screening device for people coming into a residency, because you have to really spend a lot of hours on it. If you are going to interview resident candidates, and part of your interview process is going to be spending 6 hours on a simulator, I think that would be a little intimidating for the average candidate.
Daniel W. Steen, MD, is a senior staff ophthalmologist with Henry Ford Eye Care Services. He can be reached at the Henry Ford Hospital Main Campus, 2799 W. Grand Blvd., Detroit, MI 48202; 313-916-3245.