Simulation training is the key to learning strabismus surgery techniques


Reviewed by Will Turk, MD

Strabismus surgery simulation training offers several advantages, according to Will Turk MD, an ophthalmologist and researcher in oculoplastic, orbital and ocular oncology surgery at the University of Calgary in Alberta, Canada.

“How do we currently teach strabismus surgery? asked Turk, noting that residents have traditionally been trained under the direct supervision of experienced mentors. “Most programs in Canada are basically on-the-job training. Typically, we teach OR residents on living patients. There is a graduated responsibility over time.

Some of the things to consider in strabismus surgery in pediatric ophthalmology are the length of surgery, the young age of the patient and the need for general anesthesia, Turk said during a presentation at the 32nd Virtual Jack Crawford Day, a pediatric ophthalmology update held annually and organized by the University of Toronto and the Hospital for Sick Children in Toronto, Ontario, Canada.

Traditional teaching in a strabismus lab has involved the use of rabbit heads or cadaver eyes, according to Turk.

“We don’t currently use rabbit heads for sham surgery,” Turk explained. “There are a lot of limitations to this wet lab teaching method. It takes a lot of resources to acquire the bunny heads. They only last for a limited time. They are single use. They are not easily transportable. They pose a biohazard and must be disposed of afterwards. They are relatively expensive. There is also the “ick” factor.

Turk and Christian Petropolis, MD, FRCSC, a plastic surgeon from the University of Manitoba, invented a 3D-printed silicone model to practice and teach strabismus surgery. The model offers benefits such as patient safety, accelerated learning, reduced costs, increased operating room efficiency and group learning, according to Turk.

“I think the No. 1 thing is that it improves patient safety by allowing residents to operate in a risk-free environment,” Turk said. “There’s accelerated learning because it’s an opportunity for residents to get a good foundation of surgical skills and fine motor skills before entering the operating room.

Additionally, Turk explained that there is increased efficiency and reduced costs, which is especially important when pediatric wait times are so long.

“There’s also the opportunity to learn in a group, whether it’s with other residents in their own program or across the country or even across the world,” he said.

Performing strabismus surgery in the simulation lab, like other ophthalmic surgeries, is quickly becoming the norm in ophthalmology residency programs, Turk said.

The pilot experience with the 3D printed silicone strabismus model took place during the annual meeting of the Canadian Ophthalmological Society (COS) 2017 meeting in Ottawa, Canada during the skills transfer course in strabismus created by Yi Ning Strube, MD, noted Turk.

Since the initial pilot experiment at the COS meeting, the model was used at the annual meeting of the American Academy of Ophthalmology the same year, where it was compared to traditional rabbit heads, as a means of learn how to perform strabismus surgery.

The model was also used at the World Congress of Pediatric Ophthalmology and Strabismus in 2017 in Hyderabad, India, Turk noted.

“World experts have had the opportunity to see the model and use it,” he said.

Turk and collaborators, including Strube, a pediatric ophthalmologist, and ophthalmologist Lisa Jagan, MD, FRCSC, have published data on the experience of strabismus teaching models, including the 3D printed model. Their research was highlighted on the front page of the Journal of the American Association of Pediatric Ophthalmology and Strabismus.1

Investigators asked participants to complete a validated questionnaire to assess the fidelity of the experimental model and the rabbit head. They were asked to provide global ratings of globe, conjunctiva, muscle, and scleral fidelity using a 5-point scale.

A total of 47 participants completed the questionnaire. The model head was 18% higher than the rabbit head for anatomical accuracy and 25% higher for the position of the eyes in the head. Investigators found that more experienced users were more likely to strongly agree that silicone conjunctiva effectively mimics real conjunctiva.

“The conclusion of the study was that the model provided an excellent platform for sham strabismus surgery,” Turk said. “There was model validity compared to the rabbit head model in terms of model fidelity.”

This 3D printed strabismus surgery model has now replaced the rabbit head and has been used since 2017 at the annual Strabismus Surgery Skills Transfer course taught at the AAO, and more recently at the Surgical Skills Transfer Course strabismus at the COS annual meeting in June 2022. .

The key to strabismus simulation surgery is the use of 3D printing, Turk noted. Because the cost of 3D printers has come down significantly, it’s much more viable to build the models and use them for teaching strabismus surgery, Turk said.

“We can now be doctors who are also engineers,” Turk said. “The benefit of this (3D printing) is that you can quickly prototype different designs. You can print them out. If something doesn’t work, you can come up with a new design and have a new prototype the next day. (the 3D printing) revolutionized what we did, what we were able to do and develop.

Those performing home surgery can register, for review by a preceptor at a later date, Turk noted. “The end game is to develop a program and incorporate the assessment model and tools,” he said.

The 3D-printed model will fit well with competency-based medical training, which Turk says, along with surgical simulation training, is the future of ophthalmology training in Canada.

The 3D printed strabismus surgery model is now available for academic institutions and individuals interested in strabismus surgery, funded by the nonprofit Wright Foundation for Pediatric Ophthalmology and Strabismus. Please contact Yi Ning Strube, MD, for more information on the Strab Lab Surgical Model: [email protected]


Jagan L, Turk W, Petropolis C, et al. Validation of a new 3D printed silicone eye model for strabismus surgery for simulation training. J AAPOS. 2020;24(1).3.e1-3.e6. doi:10.1016/j-jaapos.2019.10.008


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