1. OPHTHALMIC SURGICAL TRAINING:
A CURRICULUM TO ENHANCE
SURGICAL SIMULATION
MICHAEL H. GRODIN, DO,* T. MARK JOHNSON, MD, FRCSC,*
J. LANCE ACREE, MSE,† BERT M. GLASER, MD*
Traditionally surgery has been taught by gradually
increasing hands-on learning done under the ob-
servation of a senior attending surgeon. Training has
been primarily performed on actual patients under-
going surgery with supplemental skills training be-
ing performed in the context of a wet lab. This
traditional (Halsted) method, where “sheer volume
of exposure, rather than a specifically designed cur-
riculum was the hallmark of training,” has come under
increasing scrutiny as training technology and theory
have improved.1 With ever increasing complexity of
eye surgery and the zero tolerance for surgical misad-
venture, the challenge of training future eye surgeons
is rapidly increasing. The importance of competence
in ophthalmic surgical training was formally recog-
nized by the American Board of Ophthalmology in
2002 when evaluation of surgical skills was added to
the American Council of Graduate Medical Education
mandate for resident education.2–6
The emergence of new surgical simulation devices
for a variety of surgical procedures allows unprece-
dented repetition in a virtual environment so that
exciting new approaches to training can be evaluated.
To assess the most effective use of surgical simulation
during training, we followed time-tested principles
used in aviation termed the Systems Approach to
Training (SAT).7 Using the SAT concept of task
breakdown and analysis, we assembled a team of
experienced ophthalmic surgeons and flight training
consultants who developed a detailed task breakdown
of ophthalmic surgery. We analyzed each individual
task necessary to achieve the goals of each ophthalmic
surgical procedure. This included details such as how
an instrument is held, the specific movements re-
quired, the accuracy of those movements, and the risks
associated with each maneuver.
The objective of the study was to investigate
whether training performance during surgical simula-
tion can be enhanced by a curriculum developed using
an SAT, when compared with a traditional curriculum
using the standard textbooks in the field.
Methods
This study was a prospective, randomized interven-
tional study conducted at three American Council of
Graduate Medical Education accredited ophthalmol-
ogy programs (Wills Eye Hospital, Philadelphia PA;
Vanderbilt Eye Institute, Nashville TN; Harkness Eye
Institute of Columbia University, NY). Participants
included residents in ophthalmology, post graduate
fellows in vitreoretinal surgery, and attending staff
physicians (including both three retina surgeons and
three non-retina surgeons). All participants provided
written informed consent and the study was the Health
Insurance Portability and Accountability Act (HIPAA)
compliant.
Surgical simulation was performed with VRMagic’s
EyeSi௡ v2.2 (Mannheim, Germany; www.vrmagic.
com). This is a high-fidelity virtual reality simulator
that emulates ocular surgery. It includes an operative
microscope with light-emitting diode (LED) screens
that provide binocular viewing. The surgical instru-
ments are visualized within the model eye via sensors
From the *The National Retina Institute, Towson, Maryland;
and †Aviation Training Consulting, LLC Altus, Oklahoma.
Presented at the American Society of Retinal Specialists;
Cannes, France, September 2006.
The authors declare no conflicts of interest.
Reprint requests: Michael H. Grodin, DO, The National Retina
Institute, 901 Dulaney Valley Road, Suite 200, Towson, MD
21204; e-mail: Mgrodin@bmgnri.com
1509

2. that are used to gauge instrument position and move-
ment. No tactile feedback with ocular tissues is pro-
vided by the simulator. The user can select contact
lens or Binocular Indirect Opthalmomicroscope
(BIOM) visualization as well as a variety of virtual
surgical instruments such as a light pipe, forceps,
scissors, and vitrectomy hand pieces. The EyeSi௡
records performance metrics that include iatrogenic
injuries.
To highlight surgical performance, we chose re-
moval of an epiretinal membrane (ERM) as the oph-
thalmic procedure. ERMs typically produce visual
distortion because of tractional effects and secondary
edema of the macula. Surgical removal of an ERM
requires significant dexterity and poses significant risk
of iatrogenic injury because of retinal trauma and light
toxicity. To evaluate performance in this study, the
participants were tested using the highest available
difficulty level in the EyeSi௡ ERM module (level 5).
A team of experienced ophthalmic surgeons and
flight training consultants developed a surgical curric-
ulum using SAT principles. We analyzed all steps that
occurred during the surgical procedure required to
remove an ERM from the surface of the macula. After
analyzing the steps in a surgical procedure, we devel-
oped a curriculum that could be used to optimize
techniques.
In this initial study, the absence of information on
expected results prevented sample size estimations
and power calculations. To minimize bias, the partic-
ipants were randomized at the point of entry into two
groups using a random number set. At the time of
enrollment, all participants were given an entry sur-
vey. The survey (survey 1) addressed their demo-
graphic information, surgical experience, simulation
experience, and assessed their perception of simula-
tion as a training tool. The participants were then
given instructions on the basic operation of the EyeSi௡
simulator. Participants were directed to peel an ERM
to the best of their ability; no instruction on this surgical
procedure was provided to any participant during their
attempt. Performance metrics were recorded by the
EyeSi௡ software, but were not revealed to the partici-
pants. Participants in group 1 were then directed to view
a presentation based on standard surgical textbooks and
references. Participants in group 2 were directed to view
a presentation developed using SAT. In both cases,
participants were allowed to pace themselves through
the presentations without any intervention or ques-
tions answered by the investigator. Participants were
unaware of both the existence of different presenta-
tions and of their randomized assignment to a partic-
ular group. The individual participants were isolated
from each other as they progressed through the study
sequence of events, and were staggered to prevent
discussion between them.
Participants were then directed to perform a second
ERM level 5 peeling on the EyeSi௡. The same per-
formance metrics were recorded by the EyeSi௡ soft-
ware, but were not revealed to the participants. Par-
ticipants were then directed to complete a second
survey (survey 2). This survey included statements
about the effectiveness of the presentations. Partici-
pants responded to these statements by selecting one
of five responses on a Likert scale (1 ϭ strongly
disagree, 2 ϭ disagree, 3 ϭ no opinion, 4 ϭ agree,
5 ϭ strongly agree).
These statements were as follows:
1. The presentation helped me understand how to
peel an ERM.
2. The presentation influenced my performance
peeling a simulated ERM.
3. The presentation had adequate detail to support
live surgical training.
4. The presentation adequately described surgical
risks.
The primary outcome measure of surgical performance
was the percentage of the ERM removed during the
surgical simulation. Secondary outcome measures fo-
cused on the potential avoidance of complications and
were measured by the percentage of retinal damage that
occurred during the surgical simulation and the cumula-
tive time duration of light toxicity. Data analysis used the
students’ t-tests for continuous (ratio) variable data and
the Mann–Whitney U test for ordinal data (Windows
KwikStat௡). Graphs were developed in SigmaPlot௡ 10.
Results
Forty-eight individuals were enrolled in the study.
Three of the enrollees were medical students with no
ophthalmic surgery experience. Their performance
metrics were excluded from the analysis, but their
survey responses were included. The remaining 45
included 29 (64%) ophthalmology residents, 10 (22%)
retinal fellows, and 6 (13%) attending ophthalmic
surgeons. Of these, 32 (71%) were men and 13 (29%)
were women. Of the 45 participants, 37 (82%) re-
ported no prior experience with peeling an ERM;
another five (11%) reported having peeled less than
10, and three (7%) reported having peeled more than
10. Thirty six (80%) reported no prior experience with
surgical simulations, whereas nine (20%) of the par-
ticipants reported limited experience. The randomiza-
tion was applied at enrollment to all participants as
they arrived and resulted in the following distribu-
tions: group 1: 3 attending surgeons, 4 retina fellows,
1510 RETINA, THE JOURNAL OF RETINAL AND VITREOUS DISEASES ● 2008 ● VOLUME 28 ● NUMBER 10

3. 18 residents and 1 medical student; group 2:3 attend-
ing surgeons, 6 retina fellows, 11 residents, and 2
medical students.
The results are grouped into four areas: ERM re-
moval, retina damage induced through contact with
the surgical instrument, light toxicity induced via the
light pipe, and responses to survey statements about
the courseware.
The primary outcome measure for surgical perfor-
mance was the percentage of the ERM successfully
removed during the surgical simulation as recorded by
the EyeSi௡. No significant difference in the percentage
of ERM removed was noted during the first attempt
(group 1 mean 86% with SD of 24.3 vs. group 2 mean
94% with SD of 8.3, P ϭ 0.165). After SAT-based
courseware, the difference in performance of group 2
compared with group 1 was statistically significant
(group 1 mean 91% with SD of 11.7 vs. group 2 mean
97% with SD of 3.0 P ϭ 0.037) (Figure 1).
Secondary outcome measurements recorded by the
EyeSi௡ were percentage of retina damaged by instru-
ment contact with the retina and duration of light
toxicity. During the first attempt, the mean retina
damaged for group 1 was 0.76% versus the mean for
group 2 of 0.94%. During the second attempt the mean
for group 1 was 0.092% versus mean for group 2 of
0.43%. The percentage of retina damaged was not
significantly different between groups 1 and 2 on
either attempt (1st attempt P ϭ 0.771; 2nd attempt
P ϭ 0.117) (Figure 2).
Even though light toxicity is a rare occurrence
during retina surgery, its value rests in managing risk
avoidance. The EyeSi௡ defines light toxicity occur-
rences as exceeding a maximum allowable value of
calculated light energy impinging on the virtual retina.
During the first attempt mean duration of light toxicity
for group 1 was 7.44 seconds with SD of 23.0 versus
mean for group 2 of 1.3 seconds with SD of 3.04. Both
Groups improved during the second attempt with
mean for group 1 decreasing to 2.24 seconds versus
mean for group 2 improving to 0.0 seconds. The
duration of light toxicity time was not significantly
different between groups 1 and 2 on either attempt (1st
attempt P ϭ 0.2; 2nd attempt P ϭ 0.236) (Figure 3).
To determine whether the light toxicity metric and
the retina damage metric were related, separate paired
t-tests were performed on all participants’ retina dam-
age and light toxicity metrics for the first and the
second attempts. There seemed to be no statistically
significant relationship between the light toxicity met-
ric and the retina damage metric for either attempt (1st
attempt P ϭ 0.31, 2nd attempt P ϭ 0.48).
After the second simulation attempt, all participants
were asked to evaluate the utility of the courseware in
Fig. 1. Box plots showing dis-
tributions of ERM removal
metric for both attempts, by
group. Solid lines within the
boxes indicate median; dashed
line indicates mean. Whiskers
are 90th
and 10th
percentiles;
box edges are 75th
and 25th
per-
centiles. Dots are extreme val-
ues treated as outliers.
Fig. 2. Figure showing distri-
butions of retina damage met-
ric for both attempts, by
groups. Solid lines within the
boxes indicate median; dashed
line indicates mean. Whiskers
are 90th
and 10th
percentiles;
box edges are 75th
and 25th
per-
centiles. Dots are extreme val-
ues treated as outliers.
1511OPHTHALMIC SURGICAL TRAINING ● GRODIN ET AL

4. improving their ability to perform the surgical task.
Response differences to two of four survey questions
(“the presentation helped me understand how to peel
an ERM” and “the presentation adequately described
surgical risks”) were statistically significant between
groups 1 and 2 (P ϭ 0.001 for both) (Table 1, Figure 4).
Discussion
Improving surgical training across all subspecialties
of medicine has been a topic of interest. Whether in
cardiovascular surgery,8–10 urology,11–15 otolaryngol-
ogy,16,17 gynecology,18,19 or general surgery,20–23 re-
search is under way to improve the learning curve and
skills needed to perform surgery.
In designing new surgical training techniques, it is
crucial to understand the widely accepted theories of
motor skill acquisition that were pioneered by Fitts
and Posner.1,24 This three-stage theory of motor skill
acquisition is well suited to better prepare trainees for
the operating room and live patients. The three stages
are cognition, integration, and automation. During the
cognition stage, a curriculum describes each of the
steps or tasks needed to accomplish the surgical goal.
It also details the specific skills that a trainee must
learn, and defining specific risks involved. This re-
quires a great deal in more detail than is generally
available in current surgical textbooks. In the field of
aviation, procedures usually undergo a detailed task-
based analysis to breakdown all of the required pro-
cedures into the elemental steps that need to be taught
and mastered so as to guarantee successful flight.
During the integration stage, the curriculum is coupled
with deliberate practice and feedback from an instruc-
tor so that the mechanics of each individual step
becomes familiar to the trainee. In the third stage,
automation, the trainee has repeated the sequence of
tasks so many times that they no longer need to think
about the narrow intricacies of each individual step,
but performs the required series of tasks with such
speed and efficiency that they are free to think about
broad aspects of the procedure.
The goal of all surgical training programs is to
produce physicians with excellent medical judgment
and surgical dexterity. To date the majority of interest
in ophthalmology has been focused on the formal
evaluation of trainees, particularly in their medical
skills.2–4 Binenbaum and Volpe3 showed that eye-
hand coordination and intraoperative judgment are the
most commonly cited problems for ophthalmology
residents. Global Rating Assessment of Skills in In-
traocular Surgery25 and Objective Assessment of
Skills in Intraocular Surgery26 are the two methods
previously described to aid in assessing surgical com-
petence. These assessment techniques focus on better
capturing subjective feedback from mentors on the
progress of trainees. Little has been published on
attempts to gather objective performance data or to
improving the methods of training themselves. Excel-
Fig. 3. Figure showing distri-
butions of light toxicity metric
for both attempts, by groups.
Solid lines within the boxes in-
dicate median; dashed line in-
dicates mean. Whiskers are
90th
and 10th
percentiles; box
edges are 75th
and 25th
percen-
tiles. Dots are extreme values
treated as outliers.
Table 1. Statistical Analysis for Responses to Four Statements, By Group
Statement: “The presentation . . .
Group 1 (n ϭ 25) Group 2 (n ϭ 22)
U Test
pMean ␴ Mean ␴
Helped me understand how to peel an ERM” 3.00 1.12 4.14 0.77 0.00
Influenced my performance peeling a simulated ERM” 3.44 0.87 3.96 0.84 0.08
Had adequate detail to support live surgical training” 2.96 0.84 3.59 0.79 0.02
Adequately described surgical risks” 3.20 0.91 4.05 0.49 0.00
␴ ϭ estimated standard deviation.
1512 RETINA, THE JOURNAL OF RETINAL AND VITREOUS DISEASES ● 2008 ● VOLUME 28 ● NUMBER 10

5. lence in surgical performance requires objective per-
formance feedback over multiple practice sessions.
Surgical simulation is an emerging area in medical
training.27–30 The ability to allow candidates to per-
form multiple repetitions of essential tasks while
avoiding any risk to patients makes simulation ideally
suited for educating future ophthalmic surgeons. The
EyeSi௡ is a high fidelity, virtual reality surgical sim-
ulator that reproduces the experience of intraocular
surgery with remarkable accuracy.31–35 Rossi et al36
demonstrated that the EyeSi௡ has the potential to
evaluate specific surgical skills that are training re-
lated and that an improvement in surgical skill can be
achieved with training on the simulator. Park et al37
evaluated the capability of the EyeSi௡ to mimic in-
traocular surgical conditions and assess its potential
usefulness in training residents for intraocular surgery.
Their results reported that experienced intraocular sur-
geons felt that the simulator was an excellent supple-
mental teaching tool for training intraocular surgery.
Khalifa and Bogorad38 assessed virtual reality tech-
nology for its potential to reduce operating room costs
and risk to patients, as well as complementing the
apprentice (Halsted) training model.
Despite the obvious risk reduction advantages of
simulation, we are unaware of any effort to design
curriculum to leverage these advantages for ophthal-
mology. The airline industry has used simulation for
decades with excellent results. A component of the
success of simulation in improving training of pilots
can be attributed to the development of task-specific
curriculum supporting simulation training.
Our study assesses how we might harness the power
of the SAT by using task analysis to obtain better
results from simulation. The authors of the current study
anticipated that repetition on the simulator and/or famil-
iarization with peeling an ERM would result in some
natural performance improvement. However, the authors
also anticipated that task-specific courseware (outlining
procedural steps and the risks involved in each step)
would produce further significant performance gains.
Accordingly, the authors designed the study to highlight
the effect of the courseware, as opposed to the effect of
mere repetition.
The task performance metrics indicate that repeti-
tion alone was not solely responsible for performance
improvement. The participants receiving detailed,
task-specific instruction were more effective at remov-
ing the ERM (P ϭ 0.037). Both complication avoid-
ance metrics did decrease for the two groups suggest-
ing that simulation improves performance while
minimizing risk to actual patients. The participants’
subjective assessment of the courseware indicates
(P ϭ 0.001) that task analysis adds value to current
methods of instruction. Systems Approach to Training
results in a detailed mental model for the task (state-
ment 1). Also, it results in a thorough understanding of
risks associated with a surgical task (statement 4). The
positive assessment of the participants supports the
integration of task analysis into curriculum develop-
ment for surgical training with simulation.
This investigation was limited by sample size. An-
other limitation was the lack of experience with sur-
gical simulation among the participants; this may have
influenced the performance metrics due to the novelty
of the experience. The EyeSi௡ itself may be a limita-
tion due to some lack of sensitivity among some of the
performance metrics and the absence of more exten-
sive training criteria. Additionally, the research se-
quence (first simulation, presentation, second simula-
tion) in this study was only a segment of a much larger
training system, and this limited the achievable degree
of performance gain. While this study focused on
ERM peeling, the SAT designed curriculum and
EyeSi௡ are capable of performing teaching modules
for other tasks in vitreoretinal surgery and anterior
segment surgery including cataract surgery.
An integrated training system built with SAT is
composed of an interlocking array of instruction, sim-
ulation and real experience, with multiple repetitions
Fig. 4. Figure showing the re-
sponse distributions by groups
to statements 1 and 4. Solid
lines within the boxes indicate
median; dashed line indicates
mean. Whiskers are 90th
and
10th
percentiles; box edges are
75th
and 25th
percentiles. Dots
are extreme values treated as
outliers.
1513OPHTHALMIC SURGICAL TRAINING ● GRODIN ET AL

6. accompanied by performance feedback. In such a sys-
tem, gated progression between successive modules
helps to ensure deficiencies are identified with objec-
tive metrics and corrected by mandatory remediation.
The performance gain in membrane removal and
the participants’ assessment of the curriculum sup-
ports the position that the SAT enhances the power of
simulation for acquiring surgical skill. This combina-
tion of SAT with simulation seems to be a path that
could enable ophthalmology training programs to
achieve higher performance curves while minimizing
risk to patients. This study supports further research
on this coupling effect.
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