A systematic review of the effectiveness of flipped classrooms in medical education

Efficient undergraduate learning of liver transplant: building a framework for teaching subspecialties to medical students

BACKGROUND

Liver recipients may develop various diseases after transplant. However, because of inadequate study of liver transplant during undergraduate education, the quality of post-transplant care provided to these patients remains suboptimal. Herein, we introduce an innovative and integrated multimodal pedagogical approach to effectively disseminate key information regarding liver transplant to undergraduate students. The goal is to examine this approach through students' assessment in multiple dimensions.

METHODS

This prospective observational study evaluated student reactions to our pedagogical approach. Fifth-year medical students during the academic year 2015-2016 attended a 2-h session on what nontransplant doctors should know about liver transplants. The pedagogical strategy consisted of an online preclass self-learning exercise, an in-class interactive discussion (facilitated by the class teacher who is a liver transplant specialist to avoid distractions within the short-time frame), and a postclass essay assignment (to integrate and apply concepts). After the class, questionnaires were distributed to individual students to collect data, if returned, concerning the students' learning experience and feedback to improve teaching quality. Descriptive statistics, Mann-Whitney U tests, chi-squared tests, and McNemar's tests were used to analyze quantitative data. Qualitative data were content-coded through a descriptive approach using thematic analysis.

RESULTS

Of the 266 attendees, 263 (98.9%) completed the questionnaires and 182 (69.2%) provided comments. Student feedback indicated they "felt better" and "more satisfied" compared with problem-based learning (PBL) (51.0 and 63.1%, respectively) or large-lecture class (92.0 and 88.6%, respectively) approaches. Regarding confidently managing liver transplant patients in future, 80 (30.4%) and 246 (93.5%) students expressed preclass and postclass confidence, respectively (p < 0.001). The bell curve of the postclass self-assessment score of learning shifted toward right and became steeper compared with that of the preclass score (p < 0.001), suggesting students acquired considerable knowledge. The course was typically perceived to be cost-effective, practical, tension-free, and student-friendly.

CONCLUSION

This pedagogical approach effectively propagated knowledge concerning liver transplant to medical students, who expressed considerable satisfaction with the approach.

Academic outcomes of flipped classroom learning: a meta-analysis

CONTEXT

The flipped classroom (FC), reversing lecture and homework elements of a course, is popular in medical education. The FC uses technology-enhanced pre-class learning to transmit knowledge, incorporating in-class interaction to enhance higher cognitive learning. However, the FC model is expensive and research on its effectiveness remains inconclusive. The aim of this study was to compare the efficacy of the FC model over traditional lecture-based (LB) learning by meta-analysis.

METHODS

We systematically searched MEDLINE, PubMed, ERIC, CINAHL, EMBASE, reference lists and Association for Medical Education in Europe (AMEE) conference books. Controlled trials comparing academic outcomes between the FC and LB approaches in higher education were considered eligible. The main findings were pooled using a random-effects model when appropriate.

RESULTS

Forty-six studies (9026 participants) were included, comprising four randomised controlled trials (RCTs), 19 quasi-experimental studies and 23 cohort studies. Study populations were health science (n = 32) and non health science (n = 14) students. The risk of bias was high (36/37 articles). Meta-analyses revealed that the FC had significantly better outcomes than the LB method in examination scores (post-intervention and pre-post change) and course grades, but not in objective structured clinical examination scores. Subgroup analyses showed the advantage of the FC was not observed in RCTs, non-USA countries, nursing and other health science disciplines and earlier publication years (2013 and 2014). Cumulative analysis and meta-regression suggested a tendency for progressively better outcomes by year. Outcome assessments rarely focused on behaviour change.

CONCLUSIONS

The FC method is associated with greater academic achievement than the LB approach for higher-level learning outcomes, which has become more obvious in recent years. However, results should be interpreted with caution because of the high methodological diversity, statistical heterogeneity and risk of bias in the studies used. Future studies should have high methodological rigour, a standardised FC format and utilise assessment tools evaluating higher cognitive learning and behaviour change to further examine differences between FC and LB learning.

Flipping the Dental Anatomy Classroom

The development of cognitive knowledge, motor skills, and artistic sense in order to restore lost tooth structure is fundamental for dental professionals. The course of dental anatomy is taught in the initial years of dental school, and is a component of the basic core sciences program in the faculties of dentistry. The learning objectives of the dental anatomy course include identifying anatomical and morphological characteristics of human primary and permanent teeth; identifying and reproducing tooth surface details in order to recognize and diagnose anatomical changes; and developing student’s psychomotor skills for restoring teeth with proper form and function. The majority of dental schools rely on traditional methods to teach dental anatomy, using lectures to convey the theoretical component; whereas the practical component uses two-dimensional drawing of teeth, identification of anatomical features in samples of preserved teeth, and carving of teeth. The aim of the present literature review is to summarize different educational strategies proposed or implemented to challenge the traditional approaches of teaching dental anatomy, specifically the flipped classroom educational model. The goal is to promote this approach as a promising strategy to teaching dental anatomy, in order to foster active learning, critical thinking, and engagement among dental students.

Physiology learning for veterinary students: impact of guided practices on students' opinion and physiological parameters

Over recent decades, education has increasingly focused on student-centered learning. Guided practices represent a new way of learning for undergraduate students of physiology, whereby the students turn into teacher-students and become more deeply involved in the subject by preparing and teaching a practical (laboratory) class to their peers. The goal was to assess the students' opinions about guided practices and how physiological parameters change during the activity. For this objective, two experiments were performed. First, a voluntary questionnaire on guided practices was completed by the students during 2 academic years. Students could also write a free text commentary. The positive answers obtained in the questionnaire and the free commentary responses point to the effectiveness of this methodology in students' minds. Negative aspects included the time spent preparing the activity, and the stress that students experienced in the teaching role. Second, information about how the teacher-students felt before teaching the practical class was self-reported, and physiological parameters related to stress (heart rate, pulse rate, blood pressure, arterial oxygen saturation, respiratory rate, and electrocardiogram recorded to evaluate R-R interval and heart rate variability) were measured immediately before and while the practical class was taught. This evaluation reported an increase in stress during the execution of the practice. In conclusion, despite a new and stressful situation, guided practices are of interest for the students as a learning tool and for the acquisition of skills that may be of use in their later professional lives.

Analysis of satisfaction and academic achievement of medical students in a flipped class

PURPOSE

The purpose of this study was to examine the satisfaction of medical students in flipped learning and analyzed academic achievement in comparison with lecture class.

METHODS

The subjects were 40 students who participated in flipped learning during neurology course in the second year. After performing flipped learning, formative assessment was conducted and the degree of satisfaction was examined. Questionnaires of satisfaction were developed to identify the perceptions of students on flipped learning. To compare the academic achievement of students, formative assessments were conducted at the end of the flipped learning class and the lecture class. The data was analyzed by frequency and paired t-test method.

RESULTS

The students showed a high level of frequency in using lecture notes (80.6%) and lecture slides (74.2%) among the pre-class learning resources. The average score (3.89) was higher for the factor of interaction and collaboration in the classroom than for the factor of improving learning (3.62). The average score of the students in the formative assessment was 4.28 points (out of 10 points) in the lecture class, while it was 5.56 points (out of 10 points) in the flipped learning class thus showing a statistically significant difference (t=-4.203, p<0.001).

CONCLUSION

It was observed from the responses of the students that flipped learning is helpful for the interaction and collaboration in the classroom. It is expect that this result will be useful as basic data for medical school to try flipped learning in the future.

A Meta-Analysis of Outcomes Comparing Flipped Classroom and Lecture

Objective. To examine the evidence of the effectiveness of flipped classroom compared to traditional lecture. Methods. Experimental and observational studies were included and obtained through searches of PubMed, Education Resources Information Center (ERIC), and Google Scholar. Publications from January 1, 2000 through July 1, 2017 were included. Studies were eligible for this research if: (a) the study compared student outcomes using flipped classroom versus lecture and (b) at least one outcome measure was final examination score or final course score. This analysis used a random effects model with weighted mean difference (WMD) as the outcome. Results. Six studies were included in the qualitative synthesis and five were included in the quantitative synthesis. To date, there has only been one prospective randomized comparison of flipped classroom to lecture in student pharmacist education. When comparing final examination scores, there was no significant difference between flipped classroom and lecture based instruction. Only two studies examined the effect of flipped classroom compared to lecture on final course score. This analysis also found no significant difference. Conclusion. Despite a lack of prospective randomized studies, findings from this meta-analysis suggest that flipped classroom may be associated with minimal gains in student knowledge compared to lecture. These findings are important because previous research has estimated that the flipped classroom requires more time to develop and implement. Future studies using prospective randomized designs need to be conducted before widespread adoption.

Experiences of medical teachers in flipped learning for medical students: a phenomenological study

PURPOSE

The purpose of this study was to explore the experience of medical teachers in the process of adapting flipped learning method through a phenomenological approach.

METHODS

Semi-structured interviews with five medical teachers from two medical colleges and one medical school were conducted in December, 2017. Data analysis was done according to Colaizzi's descriptive phenomenological methodology.

RESULTS

A total of 160 unique significant statements were extracted. These statements generated 17 formulated meanings that were categorized into seven theme clusters and four theme categories. Main themes were: (1) teacher with high levels of passion and motivation; (2) hurdles of flipped learning: students were still passive, struggling in preparing for flipped learning; (3) positive changes from flipped learning: changes to classroom environment and teachers' reflection through experience; and (4) challenges of flipped learning: remaining tasks for teachers, expansion of flipped learning.

CONCLUSION

Through phenomenological approach, researchers were able to elucidate categories about the experience of medical teachers when attempting flipped learning. Although medical teachers did not have the exact same idea on how flipped learning was conducted and implemented, the perception of flipped learning, or difficulties in class activities, they were still wondering how they could teach students well. This study might draw more attention to flipped learning and stimulate educational and institutional supports to improve teaching and learning in medical schools.

How comprehensive are research studies investigating the efficacy of technology-enhanced learning resources in anatomy education? A systematic review

Anatomy education is at the forefront of integrating innovative technologies into its curricula. However, despite this rise in technology numerous authors have commented on the shortfall in efficacy studies to assess the impact such technology-enhanced learning (TEL) resources have on learning. To assess the range of evaluation approaches to TEL across anatomy education, a systematic review was conducted using MEDLINE, the Educational Resources Information Centre (ERIC), Scopus, and Google Scholar, with a total of 3,345 articles retrieved. Following the PRISMA method for reporting items, 153 articles were identified and reviewed against a published framework-the technology-enhanced learning evaluation model (TELEM). The model allowed published reports to be categorized according to evaluations at the level of (1) learner satisfaction, (2) learning gain, (3) learner impact, and (4) institutional impact. The results of this systematic review reveal that most evaluation studies into TEL within anatomy curricula were based on learner satisfaction, followed by module or course learning outcomes. Randomized controlled studies assessing learning gain with a specific TEL resource were in a minority, with no studies reporting a comprehensive assessment on the overall impact of introducing a specific TEL resource (e.g., return on investment). This systematic review has provided clear evidence that anatomy education is engaged in evaluating the impact of TEL resources on student education, although it remains at a level that fails to provide comprehensive causative evidence. Anat Sci Educ 11: 303-319. © 2017 American Association of Anatomists.

Evaluation of a flipped classroom approach to learning introductory epidemiology

BACKGROUND

Although the flipped classroom model has been widely adopted in medical education, reports on its use in graduate-level public health programs are limited. This study describes the design, implementation, and evaluation of a flipped classroom redesign of an introductory epidemiology course and compares it to a traditional model.

METHODS

One hundred fifty Masters-level students enrolled in an introductory epidemiology course with a traditional format (in-person lecture and discussion section, at-home assignment; 2015, N = 72) and a flipped classroom format (at-home lecture, in-person discussion section and assignment; 2016, N = 78). Using mixed methods, we compared student characteristics, examination scores, and end-of-course evaluations of the 2016 flipped classroom format and the 2015 traditional format. Data on the flipped classroom format, including pre- and post-course surveys, open-ended questions, self-reports of section leader teaching practices, and classroom observations, were evaluated.

RESULTS

There were no statistically significant differences in examination scores or students' assessment of the course between 2015 (traditional) and 2016 (flipped). In 2016, 57.1% (36) of respondents to the end-of-course evaluation found watching video lectures at home to have a positive impact on their time management. Open-ended survey responses indicated a number of strengths of the flipped classroom approach, including the freedom to watch pre-recorded lectures at any time and the ability of section leaders to clarify targeted concepts. Suggestions for improvement focused on ways to increase regular interaction with lecturers.

CONCLUSIONS

There was no significant difference in students' performance on quantitative assessments comparing the traditional format to the flipped classroom format. The flipped format did allow for greater flexibility and applied learning opportunities at home and during discussion sections.

Flipped classroom improves student learning in health professions education: a meta-analysis

BACKGROUND

The use of flipped classroom approach has become increasingly popular in health professions education. However, no meta-analysis has been published that specifically examines the effect of flipped classroom versus traditional classroom on student learning. This study examined the findings of comparative articles through a meta-analysis in order to summarize the overall effects of teaching with the flipped classroom approach. We focused specifically on a set of flipped classroom studies in which pre-recorded videos were provided before face-to-face class meetings. These comparative articles focused on health care professionals including medical students, residents, doctors, nurses, or learners in other health care professions and disciplines (e.g., dental, pharmacy, environmental or occupational health).

METHOD

Using predefined study eligibility criteria, seven electronic databases were searched in mid-April 2017 for relevant articles. Methodological quality was graded using the Medical Education Research Study Quality Instrument (MERSQI). Effect sizes, heterogeneity estimates, analysis of possible moderators, and publication bias were computed using the COMPREHENSIVE META-ANALYSIS software.

RESULTS

A meta-analysis of 28 eligible comparative studies (between-subject design) showed an overall significant effect in favor of flipped classrooms over traditional classrooms for health professions education (standardized mean difference, SMD = 0.33, 95% confidence interval, CI = 0.21-0.46, p < 0.001), with no evidence of publication bias. In addition, the flipped classroom approach was more effective when instructors used quizzes at the start of each in-class session. More respondents reported they preferred flipped to traditional classrooms.

CONCLUSIONS

Current evidence suggests that the flipped classroom approach in health professions education yields a significant improvement in student learning compared with traditional teaching methods.

Is computer-assisted instruction more effective than other educational methods in achieving ECG competence among medical students and residents? Protocol for a systematic review and meta-analysis

INTRODUCTION

Although ECG interpretation is an essential skill in clinical medicine, medical students and residents often lack ECG competence. Novel teaching methods are increasingly being implemented and investigated to improve ECG training. Computer-assisted instruction is one such method under investigation; however, its efficacy in achieving better ECG competence among medical students and residents remains uncertain.

METHODS AND ANALYSIS

This article describes the protocol for a systematic review and meta-analysis that will compare the effectiveness of computer-assisted instruction with other teaching methods used for the ECG training of medical students and residents. Only studies with a comparative research design will be considered. Articles will be searched for in electronic databases (PubMed, Scopus, Web of Science, Academic Search Premier, CINAHL, PsycINFO, Education Resources Information Center, Africa-Wide Information and Teacher Reference Center). In addition, we will review citation indexes and conduct a grey literature search. Data extraction will be done on articles that met the predefined eligibility criteria. A descriptive analysis of the different teaching modalities will be provided and their educational impact will be assessed in terms of effect size and the modified version of Kirkpatrick framework for the evaluation of educational interventions. This systematic review aims to provide evidence as to whether computer-assisted instruction is an effective teaching modality for ECG training. It is hoped that the information garnered from this systematic review will assist in future curricular development and improve ECG training.

ETHICS AND DISSEMINATION

As this research is a systematic review of published literature, ethical approval is not required. The results will be reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis statement and will be submitted to a peer-reviewed journal. The protocol and systematic review will be included in a PhD dissertation.

PROSPERO REGISTRATION NUMBER

CRD42017067054; Pre-results.

Effectiveness of flipped classrooms in Chinese baccalaureate nursing education: A meta-analysis of randomized controlled trials

BACKGROUND

In recent years, the flipped classroom approach has been broadly applied to nursing courses in China. However, a systematic and quantitative assessment of the outcomes of this approach has not been conducted.

OBJECTIVE

The purpose of the meta-analysis is to evaluate the effectiveness of the flipped classroom pedagogy in Chinese baccalaureate nursing education.

DESIGN

Meta-analysis of randomized controlled studies.

DATA SOURCE

All randomized controlled trials relevant to the use of flipped classrooms in Chinese nursing education were retrieved from the following databases from their date of inception through September 23, 2017: PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, CINAHL, the China National Knowledge Infrastructure, the Wanfang Database, and the Chinese Scientific Journals Database. Search terms including "flipp*", "inverted", "classroom", and "nurs*" were used to identify potential studies. We also manually searched the reference lists of the retrieved articles to identify potentially relevant studies.

REVIEW METHODS

Two reviewers independently assessed the eligibility of each study and extracted the data. The Cochrane risk-of-bias tool was used to evaluate the quality of the studies. RevMan (Version 5.3) was used to analyze the data. Theoretical knowledge scores and skill scores (continuous data) were synthesized using the standardized mean difference (SMD) and 95% confidence interval (CI). The statistical heterogeneity of the included studies was analyzed by calculating the I² statistic and applying a chi-square test. Publication bias was assessed by funnel plots. The quality of the combined results was evaluated using the Grading of Recommendations Assessment, Development and Evaluation system.

RESULTS

Eleven randomized controlled trials published between 2015 and 2017 were selected. All the included studies had a moderate possibility of bias due to low methodological quality. The meta-analysis indicated that the theoretical knowledge scores and skill scores were significantly higher in the flipped classroom group than in the traditional lectures group (SMD=1.06, 95% CI: 0.70-1.41, P <0.001, and SMD=1.40, 95% CI: 0.46-2.34, P <0.001). There was no significant publication bias indicated in the primary analysis. Sensitivity analysis showed that the results of our meta-analysis were reliable. The evidence grades of the results regarding the theoretical knowledge and skill scores were low and very low, respectively.

CONCLUSION

Flipped classroom pedagogy is more effective than traditional lectures at improving students' theoretical knowledge and skill scores. Given the limitations of the included studies, more robust randomized controlled trials are warranted in a variety of educational settings to confirm our findings.

Curated Collection for Educators: Five Key Papers about the Flipped Classroom Methodology

The flipped classroom (FC) pedagogy is becoming increasingly popular in medical education due to its appeal to the millennial learner and potential benefits in knowledge acquisition. Despite its popularity and effectiveness, the FC educational method is not without challenges. In this article, we identify and summarize several key papers relevant to medical educators interested in exploring the FC teaching methodology.

The authors identified an extensive list of papers relevant to FC pedagogy via online discussions within the Academic Life in Emergency Medicine (ALiEM) Faculty Incubator. This list was augmented by an open call on Twitter (utilizing the #meded, #FOAMed, and #flippedclassroom hashtags) yielding a list of 33 papers. We then conducted a three-round modified Delphi process within the authorship group, which included both junior and senior clinician educators, to identify the most impactful papers for educators interested in FC pedagogy.

The three-round modified Delphi process ranked all of the selected papers and selected the five most highly-rated papers for inclusion. The authorship group reviewed and summarized these papers with specific consideration given to their value to junior faculty educators and faculty developers interested in the flipped classroom approach.

The list of papers featured in this article serves as a key reading list for junior clinician educators and faculty developers interested in the flipped classroom technique. The associated commentaries contextualize the importance of these papers for medical educators aiming to optimize their understanding and implementation of the flipped classroom methodology in their teaching and through faculty development.

Flipped classroom or an active lecture?

Recent changes in anatomy education have seen the introduction of flipped classrooms as a replacement to the traditional didactic lecture. This approach utilizes the increasing availability of digital technology to create learning resources that can be accessed prior to attending class, with face-to-face sessions then becoming more student-centered via discussion, collaborative learning, and problem-solving activities. Although this approach may appear intuitive, this viewpoint commentary presents a counter opinion and highlights a simple alternative that utilizes evidence-based active learning approaches as part of the traditional lecture. The active lecture takes the traditional lecture, and (1) ensures the lecture content is relevant and has clear objectives, (2) contains lecture material that is designed according to the latest evidence-base, (3) complements it with additional supplementary material, (4) creates space to check prior understanding and knowledge levels, and (5) utilizes suitable technology to facilitate continual engagement and interaction. Clin. Anat. 31:118-121, 2018. © 2017 Wiley Periodicals, Inc.

Results of a Flipped Classroom Teaching Approach in Anesthesiology Residents

BACKGROUND

In a flipped classroom approach, learners view educational content prior to class and engage in active learning during didactic sessions.

OBJECTIVE

We hypothesized that a flipped classroom improves knowledge acquisition and retention for residents compared to traditional lecture, and that residents prefer this approach.

METHODS

We completed 2 iterations of a study in 2014 and 2015. Institutions were assigned to either flipped classroom or traditional lecture for 4 weekly sessions. The flipped classroom consisted of reviewing a 15-minute video, followed by 45-minute in-class interactive sessions with audience response questions, think-pair-share questions, and case discussions. The traditional lecture approach consisted of a 55-minute lecture given by faculty with 5 minutes for questions. Residents completed 3 knowledge tests (pretest, posttest, and 4-month retention) and surveys of their perceptions of the didactic sessions. A linear mixed model was used to compare the effect of both formats on knowledge acquisition and retention.

RESULTS

Of 182 eligible postgraduate year 2 anesthesiology residents, 155 (85%) participated in the entire intervention, and 142 (78%) completed all tests. The flipped classroom approach improved knowledge retention after 4 months (adjusted mean = 6%; P = .014; d = 0.56), and residents preferred the flipped classroom (pre = 46%; post = 82%; P < .001).

CONCLUSIONS

The flipped classroom approach to didactic education resulted in a small improvement in knowledge retention and was preferred by anesthesiology residents.

Revisiting the merits of a mandatory large group classroom learning format: an MD-MBA perspective

The role of classroom learning in medical education is rapidly changing. To promote active learning and reduce student stress, medical schools have adopted policies such as pass/fail curriculums and recorded lectures. These policies along with the rising importance of the USMLE (United States Medical Licensing Examination) exams have made asynchronous learning popular to the detriment of classroom learning. In contrast to this model, modern day business schools employ mandatory large group classes with assigned seating and cold-calling. Despite similar student demographics, medical and business schools have adopted vastly different approaches to the classroom. When examining the classroom dynamic at business schools with mandatory classes, it is evident that there's an abundance of engaging discourse and peer learning objectives that medical schools share. Mandatory classes leverage the network effect just like social media forums such as Facebook and Twitter. That is, the value of a classroom discussion increases when more students are present to participate. At a time when students are savvy consumers of knowledge, the classroom is competing against an explosion of study aids dedicated to USMLE preparation. Certainly, the purpose of medical school is not solely about the efficient transfer of knowledge - but to train authentic, competent, and complete physicians. To accomplish this, we must promote the inimitable and deeply personal interactions amongst faculty and students. When viewed through this lens, mandatory classes might just be a way for medical schools to leverage their competitive advantage in educating the complete physician.

Comparison between flipped classroom and lecture-based classroom in ophthalmology clerkship

BACKGROUND

In recent years, the flipped classroom method of teaching has received much attention in health sciences education. However, the application of flipped classrooms in ophthalmology education has not been well investigated.

OBJECTIVE

The goal of this study was to investigate the effectiveness and acceptability of the flipped classroom approach to teaching ophthalmology at the clerkship level.

DESIGN

Ninety-five fourth year medical students in an ophthalmology clerkship were randomly divided into two groups. An ocular trauma module was chosen for the content of this study. One group (FG (flipped group), n = 48) participated in flipped classroom instruction and was asked to watch a recorded lecture video and to read study materials before a face-to-face class meeting. They used the in-class time for discussion. The other group (TG (traditional group), n = 47) was assigned to traditional lecture-based instruction. These students attended a didactic lecture and completed assigned homework after the lecture. Feedback questionnaires were collected to compare students' perspectives on the teaching approach they experienced and to evaluate students' self-perceived competence and interest in ocular trauma. Pre- and post-tests were performed to assess student learning of the course materials.

RESULTS

More students in the FG agreed that the classroom helped to promote their learning motivation, improve their understanding of the course materials, and enhance their communication skill and clinical thinking. However, students in the FG did not show a preference for this method of teaching, and also reported more burden and pressure than those from the TG. Students from the FG performed better on the post test over the ocular trauma-related questions when compared to those from the TG.

CONCLUSIONS

The flipped classroom approach shows promise in ophthalmology clerkship teaching. However, it has some drawbacks. Further evaluation and modifications are required before it can be widely accepted and implemented. Abbreviations FG: Flipped classroom group; TG: Traditional lecture-based classroom group; TBL: Team-based learning; PBL: Problem-based learning; ZOC: Zhongshan Ophthalmic Center.