Methods and materials
The electronic medical records of Siriraj Hospital were reviewed to identify all the patients who had underwent phacoemulsification by third-year residents from 2010 to 2017.
In the Siriraj Hospital residency programme, second-year residents begin by performing extracapsular cataract extraction surgery and then take a phacoemulsification wet LAB instruction course using pig eyes in the middle of their second academic year. In their third year, the residents begin performing phacoemulsification cataract surgery. The ophthalmic surgical simulator was introduced to Siriraj Hospital in 2012 and has been used since as a supplement to traditional training. Initially, from 2012 to 2014, simulation training was not a formal requirement before real surgery. In 2015, the simulation training curriculum was developed and completion of the standard simulation training course, comprising three categories (categories A, B and C), became mandatory before residents are allowed to perform real surgeries. Details of the curriculum are shown in figure 1.
Figure 1Surgical simulation training curriculum. The standard courseware consists of three categories. In each category, regardless of the time taken, the trainee is required to achieve the minimum score three consecutive times in each step before proceeding to the next task (minimum score of 50 for category A, 70 for category B and 85 for category C). After completion of all the tasks in each category, the learner must pass the examination before they are permitted to start training in the next category. The exam consists of multiple tasks that are randomly selected by the instructor and a time limitation is set. To pass the exam, the trainees are required to finish all the tasks in the time limit with a higher score than the minimum criteria. IOL, intraocular lens.
Because of the variation in the simulation training of residents in 2012–2014, we excluded all resident operations performed during this period. We separated the remaining cases into two groups. The first group was the trained group and included cases performed during the 2015–2016 academic year by 21 residents who had additional training with the simulator. The second group was the untrained group and included cases performed by 20 residents who had no experience with simulation training during the 2010–2011 academic year, that is, before the simulator was introduced to Siriraj Hospital.
Between 2010 and 2017, there were no major changes in the wet lab curriculum, surgical equipment and surgical technique. The wet lab course was instructed by the same instructor and followed the core curriculum. Surgeons in both groups performed the operation by creating a 3 mm temporal limbal corneal incision. A peristaltic-pump-system phaco machine, 30° straight phaco tip and coaxial I/A tip were used in the surgeries.
The patients’ demographics, including age, gender and systemic disease, were recorded. The LogMAR visual acuity, ocular comorbidity, cataract grading and ocular biometry measured by the IOLMaster instrument or ultrasonography were also collected. The operation information was retrospectively reviewed for the date of the operation, laterality of the eye, anaesthetic method, phaco time and intraoperative complications.
The main outcome sought was the total rate of complications. Other outcomes, including the posterior capsule rupture rate, anterior capsulorhexis tearing, zonular dehiscence, retaining of lens material and intraocular lens (IOL) implantation methods, were also studied.
Statistical analysis was performed using SPSS statistics software. The total rate of complications and specific complications in each group were compared using χ2 test. ORs were reported as OR (95% CI). Statistical significance was defined as p<0.05. The nominal data were also compared by χ2 test and the mean interval scale data were compared using independent t-test. Logistic regression analysis was performed and multivariable regression analysis was done using the forward stepwise method.