The ‘Eye-Max’ Experience: Evolution of 3D Surgical Microscopes

The Dawn of Ophthalmic Surgical Microscopes

The sentinel advancement in ophthalmic surgical microscopes can be traced back well over 150 years ago. This first golden era of modern-day optical engineering in ophthalmology was driven by the necessity for greater magnified and stereoscopic visualisation of the eye. The turn of the 19th century brought the advent of major advancements when pioneering ophthalmologists like Alvar Gullstrand recognised the potential of magnification in improving surgical outcomes. Gullstrand’s slit lamp, developed in 1911, marked a significant milestone, enabling detailed examination of the anterior segment of the eye.¹ This innovation paved the way for further advancements in microscope technology.

Early surgical microscopes were relatively simple, offering basic magnification and illumination. However, they revolutionised ophthalmic surgery by providing surgeons with a clearer view of the intricate structures of anterior and posterior segments of the eye. This enhanced visualisation allowed for more precise surgical manoeuvres and accompanied a paralleled evolution in ophthalmic surgical instrumentation.

The Rise of Modern Ophthalmic Microscopes

Throughout the mid-20th century, ophthalmic surgical microscopes underwent continuous refinements. Advancements in optics, illumination, and ergonomics led to the development of more sophisticated and user-friendly instruments.

Optics: The introduction of high-quality lenses and prisms significantly improved image clarity and resolution. Zoom capabilities allowed surgeons to adjust magnification levels seamlessly during procedures, adapting to varying surgical needs.

Illumination: The advent of coaxial illumination, where the light source is aligned with the optical axis of the microscope, provided shadow-free visualisation of the surgical field. This greatly enhanced surgical precision and reduced the risk of inadvertent tissue damage.

Ergonomics: Early microscopes often required surgeons to maintain awkward postures, leading to fatigue and discomfort. Modern microscopes incorporated ergonomic features like adjustable eyepieces, tilting binocular tubes, and motorised focussing, promoting surgeon comfort and reducing strain during lengthy procedures.

These advancements transformed ophthalmic surgery, enabling procedures that were previously impossible or fraught with complications. Cataract, glaucoma, and vitreoretinal surgery all benefited significantly from the improved visualisation and precision afforded by modern microscopes.

“Never before in history has innovation offered promise of so much, to so many, in such a short time.”
– Bill Gates

The Digital Revolution

The advent of digital technology in the late 20th and early 21st centuries marked a new era in ophthalmic surgical microscopes. The integration of digital cameras, high-resolution displays, and advanced image processing algorithms ushered in a wave of innovation.

Heads-Up Displays

The introduction of heads-up displays (HUDs) offered projection of a magnified, high-resolution image of the surgical field directly into the surgeon’s line of sight. This eliminated the need to constantly look through the microscope eyepieces, promoting a more comfortable and ergonomic posture. In doing so, HUDs offered superior image quality, with real-time digital processing and automated brightness control capabilities. This enhances visualisation of fine structures through lowered intra-operative illumination levels, thereby also reducing the risk of retinal phototoxicity.

3D Visualisation Systems

A significant milestone was the evolution of HUDs incorporating 3-dimensional, stereoscopic visualisation including the Alcon Ngenuity (Alcon Laboratories Inc.) and Artevo 800 Digital Microscope (Carl Zeiss Meditec AG).² These systems, exemplified by the Ngenuity platform (Figure 1, above), for the first time afforded a stereoscopic, high-definition view of the surgical field, significantly enhancing depth perception and spatial awareness.^3,4 This aided in precise surgical manoeuvres, particularly in complex cases requiring intricate manipulation of delicate tissues. From a surgical perspective, these 3D visualisation systems offered the surgeon several advantages in terms of superior stereoscopic magnified view; the capacity for real-time colour manipulation; and reduced phototoxicity risk.⁵ Real-time colour manipulation in these systems also aided in highlighting specific structures or tissues, improving clarity and detail in the surgeon’s view.² The integration of multiple views on a single large monitor, potential for intra-operative optical coherence tomography (OCT) images, and surgical instrument information, further streamlined surgical workflow.²

Alcon Ngenuity 3D Visualisation System

The evolution of 3D visualisation systems in ophthalmology has been dynamic. While there is increasing innovation in the market, a current stand out and sentinel interface is the Alcon Ngenuity 3D Visualisation System. The Alcon 3D Visualisation System is a ground-breaking digital platform transforming how surgeons visualise and perform vitreoretinal surgeries. Departing from traditional operating microscopes, Ngenuity offers a heads-up, 3D experience designed to enhance precision, comfort, and patient safety.^3,4 The components of the Alcon Ngenuity 3D Visualisation System are shown in Figure 1 (above).

Ngenuity has established itself as the market leader in 3D visualisation in Australia and New Zealand,^6* with users benefiting from improved optics, ergonomics, safety, and seamless integration3,4 with existing surgical technologies and a variety of microscopes including Alcon, Leica and ZEISS.

• Enhanced image quality: The system provides surgeons with a high definition,7 stereoscopic view of the surgical field, delivering exceptional image depth, clarity, and colour contrast. It boasts a 48% increase in magnification^7**† compared to analogue microscopes, enabling surgeons to magnify delicate structures while maintaining a wider field of view. Additionally, the 5x extended depth of focus^7**† allows for effortless focus across the entire surgical area. One of the critical components to this interface is the projection of the stereoscopic images onto an HUD. For this, Alcon currently uses a 68-inch 4K LED screen. This is optimally positioned 1.2 metres from, and in-line with, the surgeon’s view (Figure 2).⁷
• Improved surgeon ergonomics: Unlike traditional microscopes that require surgeons to bend over eyepieces for extended periods, Ngenuity enables a heads-up posture, promoting better comfort and reducing fatigue during long procedures.⁸
• Reduced patient phototoxicity: Digital image processing within Ngenuity allows for surgery under reduced light conditions, minimising the risk of light damage to the patient’s eye.⁵
• Customisation and digital filters: Surgeons can personalise their viewing experience with various digital filters that highlight specific anatomical structures or tissue layers (Figure 3).⁹
• Data fusion capabilities: Advanced versions of the system incorporate Data Fusion technology, allowing surgeons to overlay real-time surgical data and pre-operative images (such as toric lens alignment and intra-operative fluidic settings) projected from the Alcon Centurion onto the live 3D view, enhancing surgical planning and precision.⁹

Applications In Eye Surgery

Three-dimensional visualisation systems have been demonstrated to have an incredible breadth and scope across multiple sub-specialities in ophthalmic surgery. There is an emerging body of literature across anterior and posterior segment surgery including cataract, glaucoma, and vitreo-retina. Furthermore, the enhanced view offered through HUD and 3D visualisation systems has shown increasing promise among extra-ocular procedures, such as strabismus and cornea.

Cataract

While 3D visualisation systems like Alcon Ngenuity have primarily been used in vitreoretinal surgery, their application in cataract surgery is gaining momentum. Current evidence highlights several benefits and comparable safety and efficacy to traditional microscopes.

The strength of evidence for 3D visualisation systems in cataract surgery has largely focussed on visualisation, patient safety, and ergonomics. The primary advantage lies in the enhanced depth perception provided by 3D visualisation. This facilitates more precise manoeuvres during critical steps like capsulorhexis creation (particularly in mature or intumescent cataracts), hydro dissection, and cortical clean-up.¹⁰ The integration of customisable digital filters can assist in various steps, such as visualising the anterior capsule during capsulorhexis or identifying residual cortex during clean-up. Furthermore, the ability of the surgeon to selectively use digital illumination modulation allows surgeons to operate under lower light levels, potentially reducing phototoxicity and improving patient comfort.^5,11,12 Most importantly, peer-reviewed published literature has demonstrated similar surgical outcomes (visual acuity, complication rates) between 3D systems and traditional microscopes, indicating no compromise in safety or efficacy.^11-13 Studies have also demonstrated a short learning curve.³ While it is not surprising that some surgeons may experience an initial learning curve when transitioning to 3D visualisation, studies suggest a relatively short adaptation period, with surgeons quickly becoming proficient.¹⁴

Glaucoma

Glaucoma surgery is another discipline in which 3D visualisation systems are gaining traction. While the evidence base is still developing, preliminary studies and expert opinions point toward several potential benefits, particularly in the realm of minimally invasive glaucoma surgery (MIGS).^15,16

The increased depth perception offered by 3D visualisation is particularly valuable in glaucoma surgery. One of the main challenges in traditional operating gonioscopy is adequate visualisation of the anterior chamber angle. The adaptation of 3D visualisation enables superior depth of field to easily identify and work within delicate structures like the trabecular meshwork and Schlemm’s canal.¹⁵ The customisable filters have also been shown in studies to aid the visualisation of natural anatomical landmarks, such as the pigmented trabecular meshwork.¹⁵ The superior magnification and clarity offered by 3D systems can facilitate identification and management of anatomical variations, enhancing the safety and accuracy of procedures like goniotomy and trabecular micro-bypass stent implantation.

Furthermore, the ability to operate under lower light levels may decrease the risk of phototoxicity, which is particularly relevant for angle-based procedures where the light source is near the iris and lens.^12,17

The importance of ergonomic benefits of a HUD and 3D visualisation are also significant in glaucoma surgery. Studies have shown reduced neck and back strain can improve surgeon comfort and concentration.¹⁸ Anecdotally, there is also improved and more natural accessibility to the surgical field through the ability to hold the intra-operative gonioscope while looking at the HUD. Thus, overcoming the need for the surgeon to sit further back, as is the case with current traditional operating microscopes when performing MIGS.

Vitreoretinal Surgery

Vitreoretinal surgery is a highly specialised and intricate branch of ophthalmology that addresses disorders of the vitreous and retina. The delicate nature of these structures necessitates exceptional surgical precision and visualisation capabilities. The integration of 3D visualisation systems has ushered in a transformative era, offering significant advancements in surgical techniques, ergonomics, and patient outcomes. Not surprisingly, the greatest volume of published literature supporting the role of 3D visualisation systems has emerged from the discipline of vitreoretinal surgery. Papers have shown the immense benefits of greater depth of field, precision, and integration with real-time adjunctive imaging, such as intra-operative ocular coherence tomography (OCT).

Specific Applications in Vitreoretinal Surgery

Retinal detachment repair: Studies have demonstrated superior visualisation of the peripheral retina and vitreous using Ngenuity, particularly in the context of pars plana vitrectomy.5,19,32 Specifically, studies demonstrated comparable outcomes between Ngenuity and a standard operating microscope in primary retinal detachment repair, including primary retinal reattachment rates, incidence of postoperative proliferative vitreoretinopathy (PVR), and final best-corrected visual acuity (BCVA). The 3D visualisation provided improved depth perception and spatial orientation, potentially facilitating delicate surgical manoeuvres through improved precision.^3,4

Internal limiting membrane peeling: Several studies have demonstrated the potential of 3D visualisation to aid superior viewing of the internal limiting membrane (ILM) during macular surgery.^20,21 Particularly when coupled with real-time intra-operative OCT, the use of HUD and 3D visualisation conferred superior anatomical and visual outcomes compared to conventional microscopes.²

Reduced phototoxicity: The real-time digital processing and automated brightness control of Ngenuity allow for lower intraoperative end illumination levels. This potentially reduces the risk of retinal phototoxicity, a concern especially in surgeries with prolonged light exposure.²²

The integration of 3D visualisation systems has ushered in a transformative era, offering significant advancements in surgical techniques, ergonomic, and patient outcomes

Real-time Intraoperative OCT

Intraoperative OCT has revolutionised vitreoretinal surgery by providing real-time, high-resolution cross-sectional images of the retina and vitreous during procedures.² Various models, including the ZEISS Artevo have the added capability for intra-operative OCT to be displayed into the HUD. This capability enables real-time feedback, allowing surgeons to monitor their manoeuvres and make necessary adjustments; minimising complications, and optimising outcomes. The enhanced visualisation of transparent structures, such as the vitreous and ILM, is another critical advantage, as these structures can be challenging to discern with other visualisation methods.²³ Intraoperative OCT also facilitates objective dynamic assessment of surgical precision. Surgeons can confirm the success of interventions like membrane peeling or retinal reattachment in real-time, allowing for immediate adjustments if needed.

Extra-ocular Procedures

There is emerging interest in the application of 3D visualisation systems for extra-ocular procedures. While there is limited published literature, the properties of a 3D HUD have potential appeal to all ophthalmic subspecialties. The author routinely uses the Alcon Ngenuity platform for strabismus surgery, and pterygium excision with conjunctival autograft. The view offered through operating under such 3D HUD enables dynamic and enhanced magnification with depth of focus superior to those gained through traditional loupes.^3,4 This undoubtedly confers benefit in complex cases, such as re-do squint surgeries in which distinguishing between pseudo tendon (false scar) and muscle belly is critically important. Ostensibly, the benefits could be extended to cases of ocular trauma and management of penetrating eye injuries. Additionally, the advantages conferred equally optimise the view for any surgical assistant.

… as with any new technology, the transition to operating under digital visualisation systems requires a learning curve for sugeons as they adapt to a new visual perspective and interface

Ergonomic Benefits

Traditional operating microscopes require the surgeon to maintain a strict posture orientated to the eyepieces of the microscope. For many surgeons, adopting these postures for extended durations have contributed to ergonomic concerns precipitating neck and back strain.^18,23-25 HUD overcomes these challenges by projecting a magnified, high-resolution image of the surgical field directly into the surgeon’s line of sight, enabling a more comfortable, upright posture. This also reduces the risk of long-term musculoskeletal issues amongst surgeons. These ergonomic advantages are particularly valuable for lengthy and intricate procedures.

Enhanced Posture and Comfort

Natural head and neck position: 3D HUD systems allow surgeons to maintain a neutral head and neck position, eliminating the need to hunch over traditional microscopes. This reduces strain on the cervical spine and minimises the risk of neck pain and musculoskeletal disorders.^18,25

Upright posture: Unlike conventional microscopes, which often require surgeons to adopt a forward-leaning posture, 3D HUD systems promote an upright seated position.^18,25 This helps maintain the natural curvature of the spine, reducing pressure on the lower back and improving overall comfort during long procedures.

Reduced eye strain: The high-resolution, large-screen display of 3D HUD systems reduces eye strain compared to peering through microscope oculars. This can help prevent headaches and fatigue, particularly during complex and lengthy surgeries.^25,26

Reduced fatigue: The ergonomic benefits of 3D HUD systems lead to decreased physical and mental fatigue, enabling surgeons to maintain focus and dexterity throughout the procedure. This can contribute to improved surgical efficiency and consistency.

Long-Term Health Benefits

Prevention of musculoskeletal disorders: The ergonomic design of 3D HUD systems can help prevent the development of work-related musculoskeletal disorders (MSDs), a common problem among ophthalmic surgeons.^23-26 MSDs can lead to chronic pain, disability, and early retirement. By promoting neutral postures and reducing strain, 3D HUD systems contribute to long-term musculoskeletal health.

Enhanced surgeon well-being: By reducing physical discomfort and fatigue, 3D HUD systems can improve the overall well-being of ophthalmic surgeons. This can lead to increased job satisfaction, reduced burnout rates, and prolonged careers.

Enhanced Surgical Education

Ophthalmic surgical education heavily relies on observation and hands-on training. The view to the trainee surgeon and their supervisor is critical in providing a platform for safe, supervised deliberate practice. Traditional surgical microscopes have long been the primary tool for visualisation during surgeries. However, the advent of 3D visualisation systems, like the Alcon Ngenuity, is transforming the landscape of surgical training and education.

3D visualisation systems also provide a more realistic and immersive surgical experience. Compared to the 2D view of conventional microscopes, the depth perception and spatial orientation offered by 3D systems allow trainees to better understand complex anatomical structures and surgical manoeuvres.²⁷ The gyroscopic mouse allows surgeons to maintain sterility and control Ngenuity’s functions while providing instructions during surgery. The capacity to record cases and later review true 3D is the ultimate platform for the surgeon and, in the case of training, a supervisor, to reflect and provide granular feedback on performance.¹⁰ The application of such technologies can also confer opportunities for ‘tele-mentoring’ whereby experienced ophthalmologists can remotely observe and provide real-time feedback during surgical procedures, reducing the need for physical co-location.²³ This improves training accessibility and efficiency, particularly in remote areas. It also enables teaching new techniques and offering continuing education for experienced surgeons. This can significantly reduce the learning curve and improve the overall comprehension of surgical procedures.²⁸

Collaborative Teaching

The heads-up display feature of 3D systems allows multiple individuals to simultaneously view the surgical field on a large, high-definition screen. This facilitates real-time teaching and discussion, enabling surgeons to demonstrate techniques, point out critical structures, and provide immediate feedback to trainees.^26,29 Additionally, the ability to record and playback surgeries in 3D creates valuable resources for post-operative review and analysis. Furthermore, for the first time, an entire surgical team (such as the scrub nurse, theatre technicians, anaesthetists) are afforded the same stereoscopic view as the primary surgeon, which ostensibly improves efficiency of the surgical case.³⁰

While challenges remain, the scope and future of ophthalmic surgical microscopes is exciting and promising

Challenges and Opportunities

While the advent of HUD and 3D visualisation systems has shown immense potential and benefit, as with any new technologies there remain barriers to uptake and opportunities for refinement. The current drawbacks include optical cost limiting accessibility, additional theatre space, and user learning curve.³¹ While early technical criticisms concentrated on image-display lag time, depth of field, and light toxicity, recent updates across multiple platforms have largely overcome these reservations. Image acquisition and interpretation can also be challenging in the presence of intraocular bleeding or other obscuring factors. However, it is acknowledged that these limitations also exist within standard operating microscopes. Similarly, as with any new technology, the transition to operating under digital visualisation systems requires a learning curve for surgeons as they adapt to a new visual perspective and interface. Despite these challenges, the potential benefits of digital visualisation, including improved ergonomics, enhanced visualisation, and reduced phototoxicity risk, are undeniable.^5,7,32

Looking to the Future

The evolution of ophthalmic surgical microscopes is dynamic. As technology continues to advance, we can anticipate further innovations that will push the boundaries of surgical visualisation and precision. There is great potential for the integration of artificial intelligence (AI) in ophthalmic surgery.³³ AI algorithms could be incorporated into microscope systems to assist surgeons in real-time decision making, image analysis, and surgical planning. The launch of the Alcon Ngenuity version 1.5 promises seamless integration of anterior and posterior segment visualisation, colour enhancements and integration with Argos biometry data. Such examples of augmented reality (AR) overlays can provide surgeons with additional information, such as anatomical landmarks, surgical guidance, and real-time patient data, directly within their field of view. Robotic assistance systems could be integrated with microscopes to enhance surgical precision and stability, particularly for complex or delicate manoeuvres. Furthermore, advancements in miniaturisation could lead to the development of more compact and portable microscope systems, expanding access to high-quality surgical care in remote or underserved areas. These potential future developments highlight the dynamic nature of ophthalmic surgical microscope technology. Continued research and innovation will undoubtedly lead to further advancements that will benefit both surgeons and patients.

Conclusion

The evolution of ophthalmic surgical microscopes has been a remarkable journey, from the early rudimentary models to the sophisticated digital visualisation systems of today. Advancements in optics, illumination, ergonomics, and digital technology have significantly enhanced surgical precision, visualisation, and patient outcomes.

The integration of HUDs, 3D visualisation systems, and intraoperative OCT represents the cutting edge of ophthalmic surgical microscope technology. These innovations offer numerous advantages, including improved ergonomics, enhanced visualisation, reduced phototoxicity risk,

and the potential for new surgical techniques. The Alcon Ngenuity 3D visualisation system represents a significant advancement in surgical visualisation technology. Its innovative features empower surgeons to operate with enhanced precision, comfort, and efficiency while prioritising patient safety.^5,7,32 As digital technologies continue to evolve, platforms like Ngenuity will play an increasingly critical role in shaping the future of surgery.

While challenges remain, the scope and future of ophthalmic surgical microscopes is exciting and promising. Continued innovation and collaboration between bioengineers, optical scientists, and ophthalmologists will undoubtedly lead to further advancements that will continue to transform the field of ophthalmic surgery, with the goal being improved patient care and clinical outcomes.

Practical Pearls for 3D Visualisation and Heads Up Displays

Spatial Planning: Before bringing the Ngenuity into the operating room, ensure adequate space is available. This includes room for the microscope’s base, arm, and head, as well as space for the surgeon, anaesthetist, and assistants to move around comfortably. Given that optimal positioning of the HUD monitor in line with the surgeon’s view is important, this may necessitate coordination with theatre staff ahead of the list in case the monitor needs to be moved from one side of the room to another. This is particularly important in small theatres where the surgeon is routinely sitting temporally in the case of cataract surgery. Secure placement: The Ngenuity is a heavy piece of equipment. Ensure it’s placed on a stable, level surface to prevent any accidental tipping during the procedure. If possible, use the provided brakes to further secure the microscope. Optimal positioning of the screen: It is imperative that the screen positioning is as close as possible and within the line of the surgeon’s eyesight, much like a batsman’s sightscreen behind the bowler’s arm in cricket. This is to ensure the surgeon adopts a natural posture without excessive rotation of the neck. It is important to adjust the microscope to the desired position before the patient is brought in. This will minimise any disruptions during the surgery and ensure the surgeon has a clear view of the surgical field from the start. Cable management: The Ngenuity comes with several cables for power, foot pedals, and other accessories. Organise these cables neatly to prevent them from becoming tangled or obstructing the surgical team. Consider using cable ties or organisers to keep them in place. White balance check: It is imperative to undertake a ‘white balance’ check at the commencement of each operating list to ensure optimal viewing for the surgeon. Remember, these are general tips. It’s always best to consult the Alcon Ngenuity user manual for specific setup instructions and safety precautions. Bonus Tip: If possible, have a dedicated team member (e.g. theatre technician) familiar with the Ngenuity’s setup and operation. This will ensure a smooth and efficient setup process, allowing the surgical team to focus on the patient’s care.