Keywords
glaucoma - microinvasive glaucoma surgery - residents - surgical experience
Glaucoma is a leading cause of blindness and ocular morbidity globally and is projected
to afflict over 110 million people worldwide by 2040.[1] Reduction of intraocular pressure (IOP), which can be accomplished through a variety
of medications, laser therapies, and surgical interventions, is currently the only
established glaucoma treatment.[2] Incisional surgical interventions are indicated when more conservative measures
fail to produce sufficient IOP reduction and in cases of patient adherence challenges.[3]
The emergence of microinvasive/minimally invasive glaucoma surgery (MIGS), has altered
the modern surgical approach to the management of primary open angle glaucoma. While
generally less disruptive to the ocular tissues albeit with more modest IOP-lowering
efficacy,[4] MIGS procedures enjoy increasing popularity and recognition by the American Glaucoma
Society as a useful addition to the glaucoma surgical armamentarium.[5] Nevertheless, there is currently no standardized required experience with these
procedures during ophthalmology residency training in the United States. The requirement
for glaucoma procedural experience put forth by the Accreditation Council for Graduate
Medical Education (ACGME) is for an ophthalmology resident to achieve a minimum of
five Filtering and/or Shunting procedures, five laser trabeculoplasties, and four
laser iridotomies during training, a standard most recently updated in 2013.[6] The degree to which U.S. ophthalmology residents are exposed to MIGS techniques
during their surgical training, and how this may affect future practice patterns and
delivery of glaucoma care is presently unknown. The purpose of this study is to survey
current U.S. ophthalmology residents regarding their experience with surgical management
of glaucoma, including MIGS techniques, and eventual practice intentions.
Methods
The study protocol was submitted to the Augusta University Institutional Review Board
and was deemed exempt from formal review. A 10-question internet-based questionnaire
was subsequently emailed to all 120 accredited U.S. ophthalmology residency programs
listed on the ACGME website at the time of study design. The survey instrument was
designed and utilized to collect responses anonymously through Qualtrics software
(Qualtrics Inc, Provo, UT). The email solicitation containing the survey link was
emailed to both the program directors and program coordinators when their contact
information was available, requesting subsequent distribution to residents in their
respective programs. The questionnaire contained questions surveying current residents
regarding their year in training, geographic area of residency program, intended practice
setting, intended subspecialty, intended style of management of glaucoma post training,
expected surgical volume of both ACGME-required glaucoma procedures (filtering/shunting
procedures, laser trabeculoplasty, laser iridotomy), and MIGS procedures, as well
as anticipated experience with specific MIGS techniques as primary surgeon ([Supplementary Fig. S1]). The survey stratified anticipated primary surgical experience in four categories:
<5, 5 to 10, 10 to 20, or >20 procedures. The survey remained open collecting responses
between January 21, 2019 and March 4, 2019. Reminder emails to residency programs
were sent at 2-week intervals during this time period. Collected survey responses
were evaluated using chi-square analysis.
Results
A total of 161 survey responses were collected. As ascertained from the ACGME website,
based on a total of 1,479 resident positions, this amounted to a 10.9% response rate
nationally. Demographics of survey respondents are reported in [Table 1]. 44.1% of respondents were third year residents, 37.3% were second year residents,
and 18.6% were first year residents. The most common intended subspecialty reported
by respondents was comprehensive (37.9%) followed by glaucoma (19.3%). Most survey
respondents reported an intention to practice in a group private practice setting
(63%) upon completion of residency training. Residents from all geographic regions
were represented, with the Southeast being the most common (29.2%) and the West being
the least common (11.8%) source of respondents, respectively. Concerning management
of glaucoma patients, a majority of respondents (70.2%) reported an intention to manage
glaucoma surgically upon completion of training. Among these respondents, 47.2% reported
an intention to manage glaucoma with less invasive techniques (e.g., laser trabeculoplasty,
phacoemulsification, MIGS), while 23.0% reported an intention to include more advanced
glaucoma procedures (glaucoma drainage device implants and trabeculectomies) in their
eventual practice.
Table 1
Demographics of survey respondents
|
Number
|
Percentage
|
|
Total US residents
|
1,479
|
|
|
Total respondents
|
161
|
10.9%
|
|
Year of training
|
|
|
|
1
|
30
|
18.6%
|
|
2
|
60
|
37.3%
|
|
3
|
71
|
44.1%
|
|
Intended specialty
|
|
|
|
General/Comprehensive
|
61
|
37.9%
|
|
Cornea/Refractive
|
22
|
13.7%
|
|
Glaucoma
|
31
|
19.3%
|
|
Oculoplastics
|
8
|
5.0%
|
|
Pediatrics/Strabismus
|
8
|
5.0%
|
|
Neuro-ophthalmology
|
1
|
0.6%
|
|
Retina (surgical)
|
25
|
15.5%
|
|
Retina (medical)
|
2
|
1.2%
|
|
Uveitis
|
3
|
1.9%
|
|
Intended practice setting
|
|
|
|
Academics
|
40
|
24.8%
|
|
Private practice–solo
|
5
|
3.1%
|
|
Private practice—group
|
102
|
63.3%
|
|
Employee
|
14
|
8.7%
|
|
Geographic region
|
|
|
|
Northeast
|
29
|
18.0%
|
|
Southeast
|
47
|
29.2%
|
|
Southwest
|
23
|
14.3%
|
|
Midwest
|
43
|
26.7%
|
|
West
|
19
|
11.8%
|
|
Intended glaucoma management
|
|
|
|
None
|
25
|
15.5%
|
|
Medical only
|
23
|
14.3%
|
|
Minimal surgical
|
76
|
47.2%
|
|
Advanced surgical
|
37
|
23.0%
|
Overall, 73.3% of survey respondents reported actual or anticipated primary surgical
experience with any of the MIGS techniques referenced in the survey item ([Table 2]). The most common technique with which residents reported experience was the iStent
(Glaukos, San Clemente, CA), at 57.8%. The second most common reported MIGS technique
was the Kahook Dual Blade goniotomy (New World Medical, Rancho Cucamonga, CA). Gonioscopy-assisted
transluminal trabeculotomy and the XEN Gel Stent (Allergan, Dublin, Ireland) were
the only other MIGS techniques with which at least 10% of U.S. ophthalmology residents
reported actual or anticipated experience ([Table 2]). Regarding cyclodestructive procedures, 75.8% and 24.8% reported actual or anticipated
experience with transscleral cyclophotocoagulation and endocyclophotocoagulation,
respectively ([Table 2]). Among traditional glaucoma surgical techniques, glaucoma drainage device implantation
was more commonly reported to be a component of U.S. ophthalmology residency training
(85.1%) than trabeculectomy (60.2.%) ([Table 2]).
Table 2
Anticipated primary glaucoma surgical procedure experience
|
No. of Respondents
|
% Respondents anticipating primary surgical experience
|
|
Cataract surgery
|
|
|
|
Phacoemulsification
|
156
|
96.9%
|
|
Shunting/filtering procedures
|
|
|
|
Trabeculectomy
|
97
|
60.2%
|
|
Glaucoma drainage implant
|
137
|
85.1%
|
|
Laser procedures
|
|
|
|
Laser Iridotomy
|
153
|
95.0%
|
|
Laser trabeculoplasty
|
156
|
97.0%
|
|
Cyclodestructive procedures
|
|
|
|
Transscleral cyclophotocoagulation
|
122
|
75.8%
|
|
Endocyclophotocoagulation (ECP)
|
40
|
24.8%
|
|
MIGS procedures
|
|
|
|
iStent
|
93
|
57.8%
|
|
iStent SUPRA
|
10
|
6.2%
|
|
CyPass
|
13
|
8.1%
|
|
Kahook dual blade
|
56
|
34.8%
|
|
Gonioscopy-assisted transluminal trabeculotomy (GATT)
|
26
|
16.1%
|
|
Trabectome
|
13
|
8.1%
|
|
TRAB 360
|
12
|
7.5%
|
|
Ab interno canaloplasty
|
8
|
5.0%
|
|
VISCO360
|
4
|
2.5%
|
|
Hydrus Microstent
|
9
|
5.6%
|
|
XEN gel stent
|
23
|
14.8%
|
|
InnFocus Microshunt
|
0
|
0.0%
|
|
Any MIGS
|
118
|
73.3%
|
|
Any MIGS/ECP
|
123
|
76.4%
|
Abbreviation: MIGS, microinvasive glaucoma surgery.
The anticipated volume performed as primary surgeon during residency of the four different
categories of glaucoma procedures considered (aqueous shunt/trabeculectomy, MIGS,
iridotomy, trabeculoplasty) was significantly different (p < 0.0001) ([Fig. 1]). The majority of respondents (73.3%) anticipated performing 0 to 10 MIGS cases
during residency. The most common anticipated primary MIGS volume performed during
residency was <5 (42.9%), followed by 5 to 10 (30.4%). The majority of respondents
(50.3%) anticipated 5 to 10 tube shunts/trabeculectomies during residency training.
Comparatively, the anticipated volume categories of trabeculoplasties and iridotomies
performed during residency was more evenly distributed among higher volume categories
([Fig. 1]).
Fig. 1 Anticipated primary surgical volume by glaucoma procedure.
Upon analysis of MIGS procedure volume by geographic region, a significant difference
was demonstrated (p = 0.037). Anticipated iridotomy volume by geographic region also reached statistical
significance in our analysis (p = 0.049). However, no significant difference was identified in the volume of aqueous
tube shunts/trabeculectomies (p = 0.17) or trabeculoplasties anticipated by geographic region (p = 0.42). Additionally, intended glaucoma management style was also not statistically
different among the different geographic regions (p = 0.19) ([Fig. 2]).
Fig. 2 Anticipated primary glaucoma surgical volume by geographic region. *p < 0.05.
As respondents' anticipated MIGS primary surgical volume was seen to vary significantly
by geographic region, we performed additional sub-analyses dividing respondents into
those with any degree of anticipated MIGS experience during residency, and those with
none. Although anticipated MIGS volume varied significantly by geographic region,
the likelihood of any MIGS exposure during residency did not vary significantly across
geographic region (p = 0.16). Intended glaucoma management style was also not found to differ significantly
between residents anticipating any MIGS experience or none (p = 0.085) ([Fig. 3]). Of the 113 respondents who reported an intention to manage glaucoma surgically
to any degree in their practice, 25 (22%) anticipated no MIGS experience as primary
surgeon during their residency training.
Fig. 3 Any anticipated MIGS experience by anticipated glaucoma practice. MIGS, microinvasive
glaucoma surgery.
Discussion
Although MIGS techniques are increasingly popular in the surgical paradigm of glaucoma
due to perceived safety and recovery benefits compared with traditional glaucoma surgical
techniques,[7] these methods are not currently a standard required component of ophthalmology residency
training in the United States. To our knowledge, no previous study has specifically
investigated the state of MIGS training during residency. Our national survey sample
suggests that while the majority of ophthalmologists in training in the United States
intend to utilize minimally invasive surgical techniques to manage glaucoma in their
practice, including MIGS, a considerable portion of such trainees may receive little
MIGS exposure during their residencies. In addition, we have observed significant
variation in the volume of anticipated MIGS procedures performed by geographic region.
The reasons underlying this geographic variability are unclear at this time and warrant
further future investigation.
Studies examining ACGME resident glaucoma case logs suggest that national glaucoma
surgical trends are also reflected at the level of residency training experience.[8]
[9] Echoing national trends of declining use of the trabeculectomy and increasing usage
of the aqueous tube shunt,[8] examination of ACGME data collected between 2009 to 2016 has shown a 20% decline
in primary filtering surgery volume, and a parallel 40% increase in glaucoma tube
shunt implantation.[9] Chadha et al reported that MIGS were not specifically tracked by the ACGME case
logs at the time of their study, nor were all MIGS procedures tracked in the Association
of University Professors of Ophthalmology glaucoma fellow case logs at that time.[9] Presently, it appears that common MIGS current procedural terminology codes are
tracked by the ACGME case log system under the general categories of “shunting” or
“filtering” procedures. The most current (2018–2019) Ophthalmology National Resident
Report released by the ACGME also provides incisional glaucoma surgery resident averages
and percentiles only under these same general categories of “filtering procedures,”
“shunting procedures,” and “other glaucoma procedures,” without further subdivision
into specific procedures or techniques utilized.[10] Thus, our survey provides unique insight regarding the actual experience and exposure
to these procedures in training programs.
The question of whether MIGS should be a component of the required primary glaucoma
surgical curriculum for U.S. ophthalmology residents is a matter that should be weighed
by surgical educators and policymakers. Because trainees are performing fewer trabeculectomies
during residency,[9] it may be reasonable to supplement this experience with an additional skillset.
Nonetheless, MIGS procedures are uniquely difficult in certain respects, for example
requiring the mastery of simultaneous gonioscopy with the nondominant hand to adequately
visualize the target tissues.[5] While residents have been shown to be capable of safely performing MIGS procedures,[11] ophthalmology is a microsurgical field in which an estimated 9% of residents may
struggle to develop technical competency,[12] and it can be argued that MIGS may be more appropriately learned during advanced
training or adopted later on in a surgeon's career.
Our study faces several limitations. A national response rate of approximately 11%
may somewhat limit the generalizability of our conclusions, although our study sample
demonstrated a relatively even representation of geographic regions and resident class
years. Additionally, a wide array of subspecialty interests was represented, without
apparent disproportionate interest in specializing in glaucoma among participating
trainees. Anticipated surgical volume was based on self-reported data and was also
stratified into four categories to simplify survey participation. This approach however,
appears to be valid, as 50% of our respondents reported an estimated 5 to 10 shunting
and/or filtering procedures as primary surgeon during residency, which is similar
to the ACGME national case log 50th percentile published for both of these procedural
categories (5 [50% percentile for these procedure categories]).[10]
