Keywords
scleral buckle - surgical teaching - surgical video - wearable device
For many years, scleral buckle surgery represented the gold-standard technique for
management of rhegmatogenous retinal detachment. However, innovations in vitreoretinal
surgery over the last few decades have shifted the surgical paradigm away from primary
scleral buckling toward vitrectomy and vitrectomy combined with a scleral buckle.[1] Nevertheless, scleral buckle surgery remains an important surgical option, particularly
for cases such as young, phakic patients, as an adjunct to vitrectomy in complex detachments,
and in retinal dialysis-associated detachments.[2]
Teaching scleral buckling techniques to trainees has become more challenging due to
the decreasing frequency of scleral buckle surgery, as well as by the challenges to
sufficiently record and review the surgeries to optimize technique. During scleral
buckle surgery, the use of an operating microscope with built-in digital recording
capability can be unwieldy; surgical maneuvers during scleral buckle surgery often
require the surgeon and the assistant to be mobile and work at an angle oblique to
the central axis of a microscope.[3] The traditional method of teaching scleral buckle surgery often requires the surgeon
and trainees to crowd around the surgical eye, limiting the visibility and audibility
of surgical instruction. Furthermore, this traditional method precludes video-assisted
review and feedback.
First-person wearable video devices may provide a convenient way to record and teach
scleral buckle surgery. Google Glass Explorer Edition (Google Inc, Mountain View,
CA) was released in 2013 as an accessory worn similarly to a pair of glasses, but
with a single small, interactive screen and camera positioned just above the user's
visual axis. Although the device faced questions of usefulness for the general consumer
and is no long sold commercially, it remains an important tool in the health care
industry, especially in surgical education.[4] GoPro HERO 4 (GoPro, Inc., San Mateo, CA) offers another option for surgical video
recording. The mountable camera, introduced commercially as a camera for outdoor and
athletic purposes, can be worn in the operating room to record surgery with the use
of a head strap.[5]
[6] Both cameras capably capture digital audio and video. As of yet, there have been
few head-to-head comparisons of these wearable devices for recording and teaching
surgery in any field of medicine or for recording ophthalmic surgery.[3]
[7]
[8]
[9] There have been no large validation studies or comparative analyses of Google Glass
and GoPro for use in ophthalmic surgery. The purpose this study was to (1) compare
the audio and visual quality of intraoperative video recordings made with Google Glass
and GoPro during scleral buckle surgery, and (2) determine the utility of intraoperative
videos recorded with Google Glass versus GoPro for teaching scleral buckle surgery
to ophthalmology trainees.
Methods
Institutional review board approval for this prospective, single-center cross-sectional
study was obtained prior to conducting the study. The study was conducted in compliance
with the Health Insurance Portability and Accountability Act, adhering to the principles
of the Declaration of Helsinki.
Nine eyes undergoing primary rhegmatogenous retinal detachment repair with scleral
buckle alone performed between 2015 and 2018 were recorded on two different hands-free
video devices, GoPro and Google Glass (device specifications in [Table 1]). The devices were worn simultaneously by a single attending operating surgeon,
either A.C. or S.J.G., as they performed the surgery. Both video and audio were recorded
simultaneously. The cases contained no identifying patient information. The videos
included patients age 18 years or older undergoing scleral buckle surgery at Wills
Eye Hospital for rhegmatogenous retinal detachment.
Table 1
Google Glass Explorer (Google Inc., Mountain View, CA) versus GoPro Hero 4 Black (GoPro,
Inc., San Mateo, CA) device specifications
|
Device specifications
|
Google Glass Explorer
|
GoPro Hero 4 Black
|
|
Maximum video resolution
|
720 p
|
1,080 p
|
|
High-definition video support
|
No
|
Yes, 4K
|
|
Field of view
|
Wide, fixed
|
Ultrawide, medium, and narrow
|
|
Video format
|
MP4 (H.264)
|
MP4 (H.264)
|
|
White balance
|
None
|
Automatic and manual adjustments
|
|
Low lux features
|
None
|
Low lux, night mode
|
|
Microphone
|
Mono
|
Mono, wind-noise reduction features
|
|
Connectivity
|
Wi-Fi and Bluetooth
|
Wi-Fi and Bluetooth
|
|
Storage
|
12 GB
|
MicroSDc
|
|
Battery life
|
Approximately 50–60 minutes of continuous video recording
|
Approximately 60–90 minutes of continuous video recording (4K resolution)
|
|
Weight
|
42 g
|
87 g
|
|
Other features
|
Prescription lenses may be used in glasses
|
|
Abbreviations: GB, gigabytes; p, pixels; SD, storage drive.
The five cases with the most complete videos from each device were chosen for inclusion
in the survey to abbreviate the survey. Each case had at least seven of the nine salient
steps filmed with both devices simultaneously of sufficient quality to be used for
grading. One case had all nine salient steps. Four of the cases did not have comparable
simultaneous videos for comparison, thus were excluded from further analysis. The
cases were then trimmed into 76 10-second clips (38 Google Glass and 38 GoPro), each
clip highlighting one of nine salient steps of scleral buckle surgery: conjunctival
peritomy, muscle isolation, suture pass, suture tie, buckle placement, Watzke's sleeve,
and scleral suture. Professional editing software was used to crop, zoom, and center
the operative eye, ensuring that clips from each device were edited the same way.
No other postrecording adjustments or enhancements of the videos were made.
Survey
From August to October 2019, an online survey was sent to ophthalmology residents,
retina fellows with the graduating year of 2018 to 2020, and current Thomas Jefferson
University medical students involved in the Ophthalmology Interest Group. All respondents
were 18 years of age and older. The study investigators were excluded. Respondents
were recruited voluntarily and informed consent was obtained. The surveys involved
a masked, side-by-side comparison of Google Glass and GoPro clips of the same surgical
step, and asked the respondent to rate video and audio quality as “excellent,” “good,”
“fair,” or “poor” based on visualization of the anatomical area and surgical process
and audio clarity; Google Glass clips were shown first and GoPro second. Additional
questions asked to respondents to evaluate the utility of these surgical videos for
education and video-assisted feedback. Respondents also completed a short multiple-choice
quiz to identify the correct order of steps of scleral buckle surgery before and after
viewing the videos. The full list of survey questions appears in [Supplementary Appendix S1] (available in the online version).
Statistical Analysis
Statistical analyses were conducted using SPSS 26 (Armonk, NY: IBM Corp.). Pre- and
posttest scores and subjective level of respondent confidence were analyzed with McNemar's
test and Wilcoxon's signed-rank test. Proportional data were tested for significance
using Chi-square analysis. Repeated measures of continuous and categorical variables
were compared using the generalized estimating equation with a binary logistic model
of favorable (“good” and “excellent”) and unfavorable (“poor” and “fair”) responses.
A p-value of ≤0.05 was determined to be statistically significant.
Results
Baseline characteristics of 36 respondents are shown in [Table 2]. Of respondents, 41.6% were ophthalmology residents, 47.2% were medical students,
2.8% were first-year retina fellows, and 8.3% were second-year retina fellows.
Table 2
Baseline characteristics of survey respondents (n = 36)
|
Demographics
|
|
Age (y)
Mean ± SD
|
27.5 (±2.7)
|
|
Gender (n = 35)
|
|
Male
|
17 (50%)
|
|
Level of training of respondent
|
|
Medical student
|
17 (47.2%)
|
|
PGY-1
|
0 (0%)
|
|
PGY-2 (first-year ophthalmology resident)
|
4 (11.1%)
|
|
PGY-3 (second-year ophthalmology resident)
|
4 (11.1%)
|
|
PGY-4 (third-year ophthalmology resident)
|
4 (19.4%)
|
|
PGY-5 (first-year retina fellow)
|
1 (2.8%)
|
|
PGY-6 (second-year retina fellow)
|
3 (8.3%)
|
Abbreviations: PGY, postgraduate year, year after graduation from medical school;
SD, standard deviation.
For the 76 different surgical clips, from the 36 trainees, there were 5,349 ratings
of audio and video quality. Regarding Google Glass, 1,273 of 2,676 (47.6%) ratings
were favorable (“good” or “excellent”), whereas 1,994 of 2,673 (74.6%) ratings were
favorable (p < 0.005, Chi-square) for GoPro.
Overall, 1,472 of 2,677 (55.0%) ratings on video quality from either modality were
favorable. Of ratings in regard to video quality, 981 of 1,338 (73.3%) found GoPro
clips to be favorable, compared with 491 of 1339 (36.7%) ratings on Google Glass clips
(p < 0.005).
Of ratings of audio quality from either modality, 1,795 of 2,672 (67.2%) found audio
clarity to be favorable. GoPro audio also had a more favorable response, with 1,013of
1,335 (75.9%) ratings of good or excellent, compared with 782 of 1,337 (58.5%) ratings
about Google Glass audio (p < 0.005).
After adjusting for age, gender, training level, and surgeon and accounting for repeated
measures with a generalized estimating equation binary regression model, type of video
recorder still had a significant influence on favorable rating with regard to both
video (p < 0.005) and audio quality (p = 0.003). Age, gender, and level of training of the respondent had no significant
influence on the model for a favorable (good or excellent) rating. After adjustment
for other above-mentioned factors, attending surgeon recording the video did have
a significant influence on favorable ratings for audio quality (p = 0.002) and for video quality (p = 0.039).
Prior to taking the survey, respondents were asked to list the nine steps of scleral
buckle surgery in the correct order given a dropdown menu. Only 1 (2.8%) of 34 respondents
who completed this pretest, listed all the steps in the correct order. Respondents
were asked to rate their confidence in knowing the steps of scleral buckle surgery
on a Likert's scale of 1 to 5, with 1 being “not at all confident” to 5 being “very
confident.” Prior to the survey, participants had a mean confidence of 1.75 ± 1.18.
After completing one full case comparing the Google Glass and GoPro clips of all nine
scleral buckle steps, respondents were given a posttest asking for the correct order
of scleral buckle steps. Of 36 who completed the posttest, 20 (55.6%) listed all the
steps in the correct order, a significantly higher proportion than the pretest (p < 0.005, McNemar's test). At the posttest, respondents reported a significant increase
in mean confidence in scleral buckle steps to 3.36 ± 1.13 (p < 0.005, Wilcoxon's signed–rank test).
If made available, 32 of 36 (88.9%) respondents would “always” or “very often” watch
brief videos of operations being performed by attending surgeons before going into
the operating room to perform the same operation. Furthermore, 31 of 36 (86.1%) respondents
found watching operative videos performed by others “extremely useful” or “very useful”
in assisting in learning.
Discussion
Our study compared the video and audio quality obtained by Google Glass versus GoPro
during scleral buckle surgery to explore their use for video-assisted teaching. Our
study determined that GoPro had significantly more favorable responses than Google
Glass for both video and audio quality. These differences persisted even when adjusting
for trainee age, gender, level of training, and attending surgeon. This finding is
in concordance with results of other head-to-head comparisons of device quality.[7]
[8]
Differences in the technical specifications of each device likely contributed to video
and audio quality. GoPro Hero 4 videos were recorded in the 1,080 pixel high-resolution
setting. Google Glass was filmed in its maximum resolution setting, 720 pixel. GoPro
also has an automatic white-balance feature that improved washout in each of the videos
while white balancing is not adjustable with Google Glass which has been previously
reported as one of its consistent limitations in surgical settings.[3] Furthermore, the GoPro has a variety of field-of-view options of which the “narrow
view” was used for surgical filming. Google Glass, by comparison, has a wide-angle
view, leading to a smaller view of the operative field.[3]
The attending surgeon who performed the surgery and recorded the video and audio was
significantly associated with video and audio rating. This highlights the fact that
the quality of recording with each device is quite user dependent. GoPro Hero 4 can
be worn midforehead. Google Glass mounts like a pair of eyeglasses. Users must adjust
to pointing each device at the surgical field and bear the ergonomic weight of the
hardware. Quality is likely associated with user-learning and ergonomic adaptability.
One limitation of each device is inherent to first person recording, the camera only
records what it is pointed at. Often during surgery, the surgeon moves their eyes
more than the head to see the operative field, so if the surgeon did not maintain
awareness about the direction of the camera relative to the operative field, the surgery
may not have been effectively recorded. Of note, GoPro can connect to a smart-phone
application which can be monitored by a third-party to see when the recording is off-center.
There are other notable differences between the two wearable devices. Google Glass
has a shorter battery life.[3]
[10] Partially to conserve battery life, Google Glass defaults to 10-second long videos.
To film a longer video, this default must be changed before each surgery.[3] Since the initiation and completion of this study, both devices have had hardware
updates that could further improve on the creation of surgical videos. GoPro Hero
8, the newest version of the device, has new attachable “mods,” including a display
screen that could be used to ensure centration during surgical filming.[11] Google Glass announced its new “Enterprise Edition 2” in 2019, which can be customized
for professional use, has higher resolution and a slightly longer battery life.[12]
The pre- and posttest in this survey objectively demonstrated that not only did confidence
in the steps of the surgery significantly increase, but also the percentage of respondents
who could correctly order the steps significantly increased. This benefit of video
review from wearable devices is consistent with other literature citing the importance
of video review in surgical education.[13]
[14] The majority of respondents felt watching self-created or other-created surgical
videos was instrumental in their training, with a majority responding they would frequently
watch videos created by attending surgeons prior to the same operation, and that they
found watching surgical videos useful in their learning.
Limitations
Our study had several limitations. The fact that our videos were recorded simultaneously
on both devices by the same surgeon did allow a greater standardization between the
Google Glass and GoPro videos. However, it would be uncommon to wear both devices
in a real-life setting and doing so may have compromised the video quality of both
devices, as it was more difficult to keep both centered at the same time. The GoPro
was more difficult to keep centered, as it is head mounted, so its favorability in
terms of video quality may be disproportionately underestimated. Our nonrandom survey,
which was voluntary and not part of standard educational evaluation, could have been
affected by response bias. It is possible that those who did not respond were less
likely to find surgical videos helpful. This could bias our results toward higher
overall favorability of surgical videos. Google Glass videos were consistently shown
first, which could potentially cause a bias leading to the respondent to classify
the GoPro videos as greater or lesser quality because of the order in which they were
viewed. Finally, our survey had a high percentage of medical student respondents,
who may have had different standards for quality of visualization, given less exposure
to ophthalmic surgery, specifically scleral buckle surgery.
Conclusion
Modern first-person wearable recording devices such as Google Glass and GoPro may
make recording quality videos not only more feasible but also more convenient. Each
recording device has its distinct advantages: GoPro appears to offer better video
and audio quality and battery life, while Google Glass may be the more ergonomic option
for prolonged use due to its lighter weight and ease of wear as glasses. The use of
Google Glass or GoPro has previously proven valuable for strabismus and oculoplastic
surgery.[9] Our findings suggest that devices such as Google Glass and GoPro can facilitate
surgical recording and improve education in scleral buckle surgery. Additional studies
would be helpful to examine the usefulness of these types of recordings during surgeries
for which an operating microscope is unavailable or unwieldy.
