Cataract extraction requires the use of an operating optical microscope to achieve the necessary magnification and visualization for the procedure. Optical microscopes typically offer a magnification in the range of 4× to 40× and oblige cataract surgeons to visualize the surgical field through microscope oculars. The surgeon uses all four extremities simultaneously throughout the procedure, resulting in a demanding and in many cases unnatural body posture, with increased cervical and lumbar stress. Such stress results in fatigue and an increased risk for the development of musculoskeletal disorders and work-related disabilities.1–4
Over the past decade, advances in digitally assisted surgery have allowed surgeons to perform what is known as “heads-up” anterior segment surgery.5 The term heads-up in this context describes the use of a three-dimensional (3D) 4K high-definition display to view the surgical field, rather than the traditional microscope oculars (the use of passive polarized 3D glasses offers stereopsis). The ergonomic set-up in the operating room of the surgeon's position with respect to the display and microscope should be addressed when performing heads-up cataract surgery to achieve unobstructed visualization (without the need for the surgeon to rotate his/her neck or torso). When an optimal set-up has been achieved, the surgeon may maintain a flexible viewing position while holding four points of bodily fixation with the extremities, which enables a more natural body posture. In 2009, Weinstock described for the first time the feasibility of using 3D visual digital visualization during anterior segment surgery,5 whereas most previously published literature describing the use of 3D visualization during ophthalmic surgery involved the posterior segment.6,7 Although numerous studies show the implementation of this visualization approach,6,7 little is known regarding its safety (reduction of complication rate), its efficiency (reduction of surgical duration), and whether there are differences when compared to the standard use of the traditional binocular microscope.
The current study evaluated the safety (complication rate) and efficiency (surgery duration) of cataract surgery using a 3D visualization system and compared the above metrics with the use of the traditional binocular microscope during cataract surgery.
Patients and Methods
This was a single-center (The Eye Institute of West Florida), retrospective case series. The chart review included consecutive patients from August 2016 to July 2017 who underwent either manual phacoemulsification or femtosecond laser–assisted cataract surgery (FLACS), with the intention to place a posterior chamber intraocular lens (IOL) (monofocal or multifocal). All surgeries were performed by a single experienced surgeon (RJW) in two operating rooms; visualization was achieved through a 3D visualization system (NGENUITY 3D visualization system; Alcon Laboratories, Inc., Fort Worth, TX) (3D group) in room 1 and a binocular microscope (traditional group) in room 2.
All patients were informed of the risks and benefits prior to cataract surgery, and they gave their written informed consent in accordance with institutional guidelines. Institutional review board approval was obtained to conduct the chart review prior to the study.
Patients were included in the study if they were older than 18 years and had a diagnosis of 2+, 3+, and 4+ nuclear sclerotic, cortical, or posterior subcapsular cataract limiting vision. All patients had implantation of either a monofocal or multifocal IOL. Patients were excluded if they had a history of pseudoexfoliation syndrome, corneal edema, Fuchs' endothelial dystrophy, or previous surgery in the operative eye. Furthermore, patients were excluded if they had a toric IOL implanted (to avoid surgical duration bias due to the use of intraoperative aberrometry and the probable need of IOL rotation in toric cases).
Cataract Surgery Technique
All procedures were performed under topical anesthesia. Standard cataract extraction was initiated by two 1.6-mm wide clear corneal incisions (main and secondary port 70° apart) performed using a diamond keratome, followed by injection of a cohesive visco-elastic device to completely fill the anterior chamber. A micro-Utrata forceps was then used to perform continuous curvilinear capsulorhexis, followed by hydrodissection and endocapsular crystalline lens rotation. The Stellaris phacoemulsification platform (Bausch & Lomb, Inc., Tampa, FL) was used for all cases with the bimanual irrigation aspiration technique to remove the crystalline lens nucleus and the cortex. A monofocal or multifocal IOL was placed in the bag in all uncomplicated cases; the cases in which complications occurred (ie, posterior capsular rupture) received anterior vitrectomy and sulcus IOL implantation.
For the cases that received FLACS, the pretreatment was performed with either LenSx (Alcon Laboratories, Inc.) or LensAR (LensAR LLC, Orlando, FL) platforms, including capsulotomy, lens fragmentation, and arcuate keratotomies for the correction of corneal astigmatism in the cases required, followed by traditional (manual) phacoemulsification as described above.
Postoperatively, all patients received the same treatment regimen consisting of a combination of an antibiotic, steroid, and non-steroidal anti-inflammatory drops.
Excel 2007 (Microsoft Corporation, Redmond, WA) and a customized Ophthalmic Data Analysis Software by Dr. Georgios A. Kounis (©2014 Ophthalmic Data Analysis Software GNEMS-Greece) were used for data collection and analysis. An evaluation for power analysis was conducted using post-hoc power assessment. All parameters followed normal distribution and a Student's t test was used to analyze and compare the outcomes between the two groups. A P value of less than .05 was considered statistically significant.
The retrospective chart review identified a total of 2,320 eyes of 1,647 patients (682 men and 965 women, aged 71.49 ± 8.99 years [range: 32 to 95 years]) that underwent either traditional (manual) phacoemulsification or FLACS followed by traditional phacoemulsification.
The 3D group included 1,673 eyes of 1,128 patients (487 men and 641 women) and the traditional group included 647 eyes of 519 patients (195 men and 324 women). Post-hoc power analysis revealed a power of 1 (100%) for both groups. In the 3D group, 870 eyes received FLACS and 803 eyes received traditional phacoemulsification. In the traditional group, 355 eyes received FLACS and 292 eyes received traditional phacoemulsification. There was no statistically significant difference between the two groups concerning surgical technique (P > .05).
Mean surgical time was 6.48 ± 1.15 minutes (range: 3 to 28 minutes) for the 3D group and 6.52 ± 1.38 minutes (range: 3 to 26 minutes) for the traditional group (Table 1). There was no statistically significant difference between the two groups in terms of surgical duration (P > .05). Mean surgical time of the FLACS cases was 6.44 ± 1.10 minutes (range: 3 to 22 minutes) in the 3D group and 6.49 ± 1.17 minutes (range: 3 to 25 minutes) for the traditional group, whereas the mean surgical time of the traditional phacoemulsification was 6.51 ± 1.19 minutes (range: 3 to 28 minutes) for the 3D group and 6.54 ± 1.19 minutes (range: 3 to 26 minutes) for the traditional group. There was no statistically significant difference between the two groups in terms of surgical duration (P > .05) between FLACS and traditional phacoemulsification.
Comparative Study Findings
There were 12 (0.72%) complications in the 3D group and 5 (0.77%) in the traditional group. There was no statistically significant difference between the two groups in terms of complication rate (P > .05). Complications for both groups included posterior capsular rapture, vitreous prolapse with need for anterior vitrectomy, and three-piece sulcus IOL implantation. No other type of complication was noted in this patient cohort (ie, bleeding, nucleus–lens fragment in the vitreal cavity, or retinal detachment). Furthermore, there was no statistically significant difference within the groups and between the groups in terms of complication rate (P > .05) when comparing the surgical approach (FLACS and traditional phacoemulsification). There were 6 complications for FLACS and 6 complications for traditional phacoemulsification in the 3D group, and 3 complications for FLACS and 2 complications for traditional phacoemulsification in the traditional group.
There has been tremendous progress and evolution in cataract microsurgery over the past century, with the advent of phacoemulsification, IOLs,8 femtosecond lasers,9 intraoperative aberrometry,10 and other tools that allow surgeons to improve safety and outcomes of cataract surgery.11 However, one aspect of the procedure that has seen little innovation is microscopic visualization. Lately, this arena also has advanced with the introduction of a 3D digital microscopic imaging system allowing for heads-up stereoscopic surgical field visualization on a flat panel display. The history of heads-up 3D cataract surgery dates back to 2007 where the first cases were performed by Wein-stock on a 510k cleared prototype 3D heads-up display system.5 The initial visualization system comprised a 3D camera hooked to the surgical microscope head via an oculars bridge adapter and the 3D signal was sent to a pair of dual rear projection cameras that sent the images to a large screen. At that time, the image had limited contrast, insufficient resolution, and a slight delay.
There has been remarkable progress concerning this technology since 2007, including introduction of a full 4K resolution 3D camera with viewing on a 55-inch OLED flatscreen monitor. The resolution, contrast, and overall image quality now approach that of the surgical microscope, whereas there is no detectable delay to the user. Over the past few years, retina and anterior segment surgeons have been embracing this technology and there is a slow but steady movement toward heads-up 3D microsurgery in ophthalmology.6,7 Other subspecialty groups (eg, neurosurgery) are also using this technology.12
There are several advantages to operating on a heads-up 3D system, with the most important being that surgeons no longer need to put themselves in an awkward and uncomfortable position having to look through the oculars of the microscope.1–4 An ergonomic set-up in the operating room is paramount to achieve unobstructed visualization of the display by the surgeon. This initially may be challenging because the head of the microscope stands between the surgeon and the display; proper placement of the display, the patient, and the surgeon should be accomplished to optimize the surgeon's view and body comfort. It is well known that performing microsurgery through the oculars of a microscope commonly results in an uncomfortable body posture, causing pain, discomfort, and often the inability to relax and perform a surgery in a comfortable manner.1–4 In addition, it has been proven and documented throughout the literature that surgeons who operate repetitively through a microscope have a higher incidence of chronic back, neck, and spine issues.1–4 The disability impact and the limitations on a surgeon's career is significant when the cumulative effects of placing one's body in this uncomfortable and unnatural position are added up over the years. This has led to early retirement of surgeons and the need for pain management surgeries and other chronic disabilities.1–4 With the 3D system, the surgeon is able to sit back in a more comfortable position with the ability to move the body and neck freely while being able to maintain good visualization of the surgical field.
The current study proved that visualization through a 3D display for cataract surgery has similar safety and efficiency when compared to the traditional binocular microscope. Surgical duration when using the 3D system was not significantly different compared to the traditional microscope, whereas the complication rate between the two approaches was not statistically different and the findings were independent of the surgical approach following either FLACS or traditional phacoemulsification. The above provides proof of concept that heads-up cataract surgery is safe, not time-consuming, and may overcome several disadvantages of the traditional microscope (eg, surgeons' fatigue, work-related disabilities, and visualization limitations).
Other obvious advantages when performing heads-up cataract surgery are that the surgeon's peripheral vision is in play throughout the procedure and the ability to have a more natural passing of instruments between the surgical technician and the surgeon. In addition, surgeons are able to operate at much higher magnifications comfortably; ocular microscopes under high magnification lead to tremendous amounts of copiopia and asthenopia and challenges of trying to focus under high magnifications.6,7 With the 3D screen being 3 to 5 feet away from the surgeon, there is the ability to magnify the image to a high magnification but not experience any of the discomfort or eyestrain when doing maneuvers under this magnification (Figure A, available in the online version of this article).6,7
Image showing a surgeon using a three-dimensional visualization system during cataract surgery. The high definition three-dimensional screen, being 3 to 5 feet away from the surgeon, has the ability to magnify the image to a high magnification and offer the surgeon a natural body posture when operating.
Additionally, the 3D operating system does not limit the view of the surgical field only to the surgeon; all observers who are looking at the screen can also benefit from the visualization system. This includes the surgical technicians and nurses in the operating room who are now able to be part of the surgical procedure and to have a better understanding of the surgical steps, which in turn facilitates the passing of instruments and preparation of future steps (ie, IOL loading). Furthermore, residents, fellows, other eye surgeons, and industry personnel are also able to observe the surgery in real time just as the surgeon experiences it.6,7,12 This allows for tremendous collaboration and opportunities for teaching, and provided the opportunity for young surgeons to be observed and supervised by experienced surgeons, which will expedite the learning process and avoid complications for patients.
The current study is limited by its retrospective nature and the fact that only one experienced surgeon used both visualization approaches. Furthermore, the implementation of a new technology introduces limitations such as its learning curve; for this technology specifically, another limitation is the set-up of the 3D display with respect to the microscope and the surgeon. The above is crucial to achieve unobstructed visualization while maintaining a more flexible body posture (without the need for the surgeon to rotate his/her neck or torso). The current cohort demonstrates that heads-up cataract surgery through a 3D visualization display has similar safety and efficiency to the gold standard surgical microscope. Further prospective studies are required to assess whether the implementation of this technology may overcome work-related disabilities and provide a new educational tool in ophthalmology.
- Chatterjee A, Ryan WG, Rosen ES. Back pain in ophthalmologists. Eye (Lond). 1994;8:473–474. doi:10.1038/eye.1994.112 [CrossRef]
- Dhimitri KC, McGwin G Jr, McNeal SF, et al. Symptoms of musculoskeletal disorders in ophthalmologists. Am J Ophthalmol. 2005;139:1:179–181. doi:10.1016/j.ajo.2004.06.091 [CrossRef]
- Chams H, Mohammadi SF, Moayyeri A. Frequency and assortment of self-report occupational complaints among Iranian ophthalmologists: a preliminary survey. MedGenMed. 2004;6:1.
- Sivak-Callcott JA, Diaz SR, Ducatman AM, Rosen CL, Nimbarte AD, Sedgeman JA. A survey study of occupational pain and injury in ophthalmic plastic surgeons. Ophthalmic Plast Reconstr Surg. 2010;27:1:28–32. doi:10.1097/IOP.0b013e3181e99cc8 [CrossRef]
- Weinstock RJ. Heads up cataract surgery with the true vision 3D display system. In: Weinstock RJ. Surgical Techniques in Ophthalmology-Cataract Surgery. New Delhi, India: Jaypee-Highlights Medical Publishers, Inc.; 2009:124–128.
- Kumar A, Hasan N, Kakkar P, et al. Comparison of clinical outcomes between “heads-up” 3D viewing system and conventional microscope in macular hole surgeries: a pilot study. Indian J Ophthalmol. 2018;66:1816–1819. doi:10.4103/ijo.IJO_59_18 [CrossRef]
- Palácios RM, de Carvalho ACM, Maia M, Caiado RR, Camilo DAG, Farah ME. An experimental and clinical study on the initial experiences of Brazilian vitreoretinal surgeons with heads-up surgery. Graefes Arch Clin Exp Ophthalmol. 2019;257:473–483. doi:10.1007/s00417-019-04246-w [CrossRef]
- Zvornicanin J, Zvornicanin E. Premium intraocular lenses: the past, present and future. J Curr Ophthalmol. 2018;30:287–296. doi:10.1016/j.joco.2018.04.003 [CrossRef]
- Agarwal A, Jacob S. Current and effective advantages of femto phacoemulsification. Curr Opin Ophthalmol. 2017;28:49–57. doi:10.1097/ICU.0000000000000333 [CrossRef]
- Hemmati HD, Gologorsky D, Pineda R 2nd, . Intraoperative wavefront aberrometry in cataract surgery. Semin Ophthalmol. 2012;27:100–106. doi:10.3109/08820538.2012.708809 [CrossRef]
- Liu YC, Wilkins M, Kim T, Malyugin B, Mehta JS. Cataracts. Lancet. 2017;390:600–612. doi:10.1016/S0140-6736(17)30544-5 [CrossRef]
- Nossek E, Schneider JR, Kwan K, et al. Technical aspects and operative nuances using a high-definition three-dimensional exoscope for cerebral bypass surgery [published online ahead of print December 3, 2018]. Oper Neurosurg (Hagerstown). doi:10.1093/ons/opy342 [CrossRef]
Comparative Study Findings
| 3D group||6||6||12||> .05|
| Traditional group||3||2||5||> .05|
P||> .05||> .05||> .05|
|Surgical time (min)|
| 3D group||6.44 ± 1.10||6.52 ± 1.19||6.48 ± 1.15||> .05|
| Traditional group||6.49 ± 1.17||6.54 ± 1.19||6.52 ± 1.38||> .05|
P||> .05||> .05||> .05|