Simulators supplement ocular surgery training

The virtual eye environment makes surgery feel realistic to residents, but more sophisticated software is needed, some physicians say.

Surgical simulators, used with the proper instructional curriculum, will be a part of the future of ophthalmic surgery training, according to physicians and educators familiar with the systems. One simulator for ophthalmic surgery is in use in several residency programs, and others are under development.

“Current systems for training ophthalmic surgeons are antiquated and in need of reevaluation,” said Bert M. Glaser, MD. “However, the availability of a high-fidelity simulator is not enough. The simulator must serve as a vehicle for the ophthalmology profession to take advantage of lessons learned by high-reliability organizations such as commercial aviation.”

Dr. Glaser and other ophthalmic educators and researchers have taken lessons from the aviation industry, combining surgical simulators with technologically advanced curricula and old-fashioned mentoring to train residents. Dr. Glaser and other spoke to Ocular Surgery News about the current state and future prospects for ophthalmic surgical simulators.

Today’s technology

One simulator, VRmagic’s EYESI, has been in use for about 2 years at Dr. Glaser’s National Retina Institute (NRI), where the faculty has designed a curriculum and performed studies to evaluate its effectiveness.

“The emergence of a high-fidelity simulator for intraocular surgery, VRmagic’s EYESI, allows unprecedented repetition of procedures in a virtual environment,” Dr. Glaser said in an e-mail interview with Ocular Surgery News.

Repetition without endangering a live patient is the primary benefit of surgical simulators, many users say. Markus Schill, PhD, of VRmagic, told OSN that this is the goal of the EYESI.

“In its current development state, EYESI ‘replaces the patient’ in the training process, while providing a realistic setup and surgical experience,” Dr. Schill said.

VRmagic currently has software for vitrectomy simulation, as well as a preliminary demonstration of cataract surgery simulation that is compatible with the system’s existing hardware. The final version of the cataract module is expected to be completed soon, Dr. Schill said.

The simulator consists of a microscope-like viewer above a rubber eyeball, with grommets into which instruments are inserted. The virtual microscope looks into a computer-generated eye and is controlled using pedals.

“As you’re performing a particular procedure, it reacts to your movements,” Craig E. Geist, MD, told OSN in an interview. “It basically allows the procedure to unfold according to the technique you’re using. You may create a problem – you may injure the retina, for instance. Then you have to learn how to get yourself out of the trouble that you created.”

Dr. Geist, the chairman of ophthalmology at George Washington University, where the system is in use, said residents feel they have a better sense of how to perform a procedure after using the simulator.

The simulator has also helped Orbis International train surgeons in the developing world, said Eugene M. Helveston, MD, in an interview.

“We’ve been able to use it in four programs internationally, and in each one of them it’s been popular among the students, particularly the younger doctors who don’t usually get near the operating room,” he said. “It gives them a chance to get their hands on something and do something exciting.”

Digital image a resident would see using the force feedback model designed by Drs. Reinig and Taravella	A student uses the force feedback simulator designed by Drs. Reinig and Taravella. The small robotic arm attached to the instrument provides a physical reaction corresponding to her movements. Images: Reinnig K, Taravella MJ
A trainee at the National Retina Institute uses VRmagic’s EYESI simulator. The monitor to his right can project a simulation of the vitrectomy or phaco control panel or, as is shown here, the surgical view the trainee is seeing through the microscope.	The “virtual patient” in the EyeSI simulator. The instruments are inserted into the rubber “eye” to simulate vitrectomy.
Image: Glaser B	Image: VRMagic

Military role

“What we’re trying to do is develop the manual skills outside of the operating room,” said Robert A. Mazzoli, MD, FACS. “So the residents are not trying to learn the basic skills at the time that they’re doing the operation. Simulation allows us to do that.”

Dr. Mazzoli is an associate professor at the Uniformed Services University and affiliated with the Madigan Army Medical Center in Washington State. In an interview with Ocular Surgery News, he said the Madigan Army Medical Center was scheduled to try a new surgical simulation system from Melerit Medical, called PhacoVision, beginning in April.

PhacoVision is currently in use in three residency programs in Sweden, where it has demonstrated validity concurrent with other methods of resident training, according to John Cook of Simulution, the distributor of the device. It was not in use by any U.S. facilities at the time this article was written, but Mr. Cook said he hoped to have users soon.

PhacoVision allows the simulation of phacoemulsification, lens cracking and aspiration of lens materials. Prior to each simulation, parameters such as density of cataract, pupil size and strength of zonule can be set and saved to develop a virtual patient library. The system also allows adjustment of parameters associated with several complications in a complication library. Mr. Cook said work is in progress to add to each library, as well as increasing selections in an instrument library. The system currently measures 35 performance metrics that can be used for curriculum assessment, he said.

Fine-tuning technology

VRmagic’s demonstration cataract surgery software has several components, including a capsulorrhexis simulation designed by Roger Webster, PhD, and Joseph W. Sassani, MD.

“I’ve been teaching residents surgery for 25 years, and the capsulorrhexis in particular is the most difficult part of the operation,” Dr. Sassani said in an interview with OSN. “It’s the very beginning of the operation. If that doesn’t go well, the rest of the operation usually goes the same way.”

Dr. Sassani brought his idea for capsulorrhexis simulation to Dr. Webster. The pair learned about the existing EYESI hardware, and they built the capsulorrhexis software to work with VRmagic’s hardware.

“The feedback we got from people who actually train residents was, ‘Wow, have I been waiting for this for a long time,’” Dr. Sassani said. “It should add about 5 years to the average life span of someone who teaches resident surgery.”

Dr. Sassani said his goal was to teach residents the eye-hand coordination needed to perform the task.

“We want them, while they’re working, to develop the same muscle memory that they would use in the operation,” he said. “You want the movements they do in the simulation to be very close to the real world.”

Dr. Geist said there are features of the cataract simulation system that could be improved. He noted that in the cataract module the software stops after a capsular rent is created, not allowing for repair, and it lacks flap creation prior to the capsulorrhexis.

Dr. Schill said VRmagic is working to create that segment of the program.

“There are some features about it that are not as optimum as they could be,” Dr. Geist said. “On the other hand, it teaches you stereo depth. It teaches you how to tissue react. It teaches you to be precise in creating the radius for the capsulorrhexis.”

Dr. Geist said he was so convinced of the reality of the experience after simulating a capsulorrhexis that he looked for the capsule at the end of the virtual instrument.

Feeling feedback

Some surgeons maintain that visual recognition and performance of surgical movements are the most important factors in surgical simulation. Others say the surgery is not realistic enough if the residents cannot feel the tissue reacting.

“In my experience, particularly with intraocular surgery, the force feedback is almost nothing,” Dr. Helveston said. “There’s so little force involved that it’s what you see, not what you feel.”

In contrast, Nicholas J. Volpe, MD, head of the American Academy of Ophthalmology’s task force on simulation, said force feedback in simulation is “critical.”

“As much as you use your eyes, you use the way things feel as you’re deciding how hard to push, pull, twist or turn,” he said.

Michael J. Taravella, MD, and Karl Reinig, PhD, of the University of Colorado, are in the process of developing a simulator for ophthalmic surgery that will feature force feedback, similar to a laparoscopic simulator designed by Dr. Reinig that is already in wide use.

“We are very much into a virtual environment,” Dr. Reinig said in an interview with OSN. “You’ll make your own portal in the eye, and you’ll feel it. It will deform, and it will be able to bring in many different pathologies and pressures because we control everything. It’s all virtual.”

Dr. Reinig explained that, in his system, instruments traditionally used by ophthalmologists are attached to a robot, which provides the necessary pressure feedback to simulate the ocular environment.

Collaborating on the design, Dr. Taravella has provided direction regarding when and where force feedback is appropriate.

The co-designers have broader goals for their simulator, Dr. Taravella said.

“We’re trying to make it affordable. That’s one of our goals.” he said. “We also want to make a system that you can practice at home with.”

The developers are currently seeking funding to move forward with their simulator, and they hope to have a demonstration model for display during the AAO meeting in the fall.

The digital image a resident would see using the EYESI simulator. This is an epiretinal membrane peel.	Wenhua Li, MD, a staff ophthalmologist on the Orbis flying eye hospital, uses the EYESI simulator in Varna, Bulgaria, in 2005. This was the first Orbis program on which the simulator was used.
Image: VRMagic	Image: Orbis

Curriculum vital

Dr. Glaser said the EYESI is “an excellent simulator that is continuing to improve.” However, he and others noted that the simulator alone is not enough.

“It must be connected with a comprehensive instructional system designed specifically to optimize the advantages of the simulator,” Dr. Glaser said. “Otherwise the simulator becomes a game and does not reproducibly enhance performance.”

Educators at NRI have performed “extensive studies,” to be published shortly, Dr. Glaser said, “that validate the role of instructional systems based upon task breakdown and analysis coupled with surgical simulations in improving performance.” Data have been collected on trainees at all levels at NRI and other training programs around the country, he said.

At NRI, Dr. Glaser and colleagues have developed a “gated system,” in which the simulator is used within a curriculum designed to have each resident fully complete a level of skill, including everything from how to hold an instrument to the accuracy of movements within surgery, before moving on to the next level.

At George Washington University, Dr. Geist said, the EYESI system is being studied for its effectiveness. Residents are videotaped before and after simulator training for comparison. The study is being extended to include medical students with no surgical experience in order to study the simulator’s effectiveness on psychomotor control, he said.

“The simulator really needs to be validated as a surgical teaching instrument,” Dr. Geist said. “Hopefully residents will be able to improve their reaction time, minimize excess movement of their hands. They could also evaluate their tremor – all those things you’d like to have under control before you put them into a surgical case with patients.”

Dr. Helveston pointed out that “nobody knows what the currculum should be” for use with surgical simulators. He said Orbis is sponsoring research on the use of the VRmagic simulator at Bellview Hospital in New York, “attempting to learn just how these simulators should be used in resident education, as well as the type of curriculum to be employed.”

Dr. Taravella said that he and Dr. Reinig are developing not only a simulator, but also a “virtual mentor.”

“While a student is practicing a cataract wound, for example, he will be able to access videos, animation and text; in other words, a virtual attending to show how to do this part of the procedure,” Dr. Taravella said.

Similarly, Dr. Schill of VRmagic said the EYESI simulator offers an import function for residency programs to provide multimedia instructional materials for their residents.

In addition to training new surgeons, simulators can also potentially be used to educate and refresh experienced surgeons, Dr. Mazzoli said. For example, he said, the simulator could be used to restore microsurgical skills in Army surgeons who spend months away from delicate microsurgical procedures while they are deployed.

Dr. Helveston talked of virtually sending residents into an intensive care newborn nursery to check the retinas of premature infants, “something that would be totally impractical, impossible to do in reality.”

Dr. Volpe, of the AAO’s task force, said the AAO does not see simulation itself as an endpoint. Along with procedural simulation there must be cognitive simulation and simulation of the entire operating room environment. All of those things are components of being a surgeon, he said.

“Simulation has to exist on a number of different levels,” Dr. Volpe said. “At this point, it does not seem like it can replace or in any way substitute for real surgical education. It will be an adjunctive tool.”

For more information:

• Bert M. Glaser, MD, can be reached at National Retina Institute, 901 Dulaney Valley Road, Suite 200, Towson, MD 21204; 410- 337-4500; fax: 410-339-7326; e-mail: bglaser@bmgnri.com. Dr. Glaser has no direct financial interest in the products mentioned in this article.
• Markus Schill, PhD, is an employee of VRmagic GmbH. He can be reached at VRmagic, Augustaanlage 32, 68165 Mannheim, Germany; 49-621-400416-0; fax: 49-621-400416-99; e-mail: schill@vrmagic.com; Web site: www.vrmagic.com.
• Robert A. Mazzoli, MD, FACS, can be reached at Madigan Army Medical Center, Building 9040, Fitzsimmons Drive, Tacoma, WA 98431; 253-968-1760; fax: 253-968- 1451; e-mail: robert.mazzoli@us.army.mil.
• Craig E. Geist, MD, can be reached at George Washington University, Department of Ophthalmology, Burns Building, Floor 2-a, Washington, DC 20037; 202-994-4050; fax: 202-994-4065; e-mail: cgeist@mfa.gwu.edu.
• Eugene M. Helveston, MD, can be reached at 702 Rotary Circle, Indianapolis, IN 46202; 317- 274-1214; fax: 317-274-1111; e-mail: ehelveston@msn.com.
• John Cook is an employee of Simulution, the distributor of the PhacoVision device made by Melerit Medical. He can be reached at Simulution, 16173 Main Ave. SE, Prior Lake, MN 55372; 877-207-5100; fax: 952-447-1996; e-mail: jcook@simulution.com; Web site: www.simulution.com.
• Roger Webster, PhD, can be reached at the Department of Computer Science, D&E Communications Wing, Caputo Hall, Millersville University, Millersville, PA 17551; 717-872-3539; fax: 717-872-3149; e-mail: roger.webster@millersville.edu.
• Joseph W. Sassani, MD, can be reached at Penn State Hershey Medical Center, 500 University Drive, Hershey, PA, 17033; 717-531-8783; fax: 717-531-5475; e-mail: jsassani@psu.edu. Dr. Sassani has no direct financial interest in the products mentioned in this article. Pennsylvania State University and Millersville University hold the intellectual property rights to Dr. Sassani and Webster’s software.
• Nicholas J. Volpe, MD, can be reached at University of Pennsylvania, Department of Ophthalmology, Hospital of the University of Pennsylvania, 2 Gates, 3400 Spruce St., Philadelphia, PA 19104; 215-662-8042; e-mail: nickvolp@mail.med.upenn.edu.
• Michael J. Taravella, MD, can be reached at the Rocky Mountain Eye Institute, University of Colorado, Health Sciences Center at Fitzsimons, 1675 N. Ursula St., Aurora, CO, 80045; 720-848-2066; 720-848-5014; e-mail: michael.taravella@uchsc.edu. Dr. Taravella has no financial interest in the products mentioned in this article.
• Karl Reinig, PhD, can be reached at the Center for Human Simulation, Health Sciences Center at Fitzsimons, Center for Human Simulation, Mail Stop F435, P.O. Box 6508, Aurora, CO 80045; 303-724-0514; karl@visiblehuman.org.

• Katrina Altersitz is an OSN Staff Writer who covers all aspects of ophthalmology.