A 3D display system (heads-up surgery / 3D digital microscopy) in ophthalmic surgery is a method in which the optical system of the surgical microscope is captured by a camera and displayed on a large 3D monitor, allowing the surgeon to operate while viewing the monitor. The surgeon does not look directly through the eyepieces of the microscope but wears polarized or liquid crystal shutter 3D glasses to view the monitor while performing surgery.
Historical background: The concept of heads-up surgery was first reported by Weinstock et al. in 2010. Subsequently, its application to vitreoretinal surgery was reported by Eckardt and Paulo, and it has spread throughout the ophthalmic field.
In conventional optical microscope surgery, the surgeon must keep their eyes close to the eyepieces and maintain a forward-leaning posture for long periods. The 3D display system is a technological innovation that fundamentally eliminates this postural burden.
In conventional microscope surgery, the surgeon maintains a forward-leaning posture with eyes close to the eyepieces, whereas in heads-up surgery, the surgeon operates while viewing a large 3D monitor in a natural posture with the head raised. This reduces postural strain on the neck and lower back, and also facilitates simultaneous observation by multiple people for educational purposes.
The main advantages of the 3D display system compared to conventional optical microscopes are listed below.
Ergonomics (Posture Improvement): 62% of ophthalmologists have cervical symptoms, making surgeon health maintenance a serious issue. The 3D display system allows surgeons to operate in a natural seated posture with their head raised, significantly reducing strain on the neck and lower back.
Contribution to Education and Collaboration: Surgical field images can be simultaneously output to multiple monitors. Instructors and trainees can share the same image while performing surgery, improving educational efficiency. Visiting observers and operating room staff can also view the intraoperative situation with the same field of view.
Digital Image Enhancement: Real-time processing can be applied to digital images captured by the camera. Contrast enhancement, noise reduction, digital filtering, and color correction can be applied during surgery, and are used to improve the visibility of internal limiting membrane (ILM) staining.
Reduction of Retinal Light Exposure: The 3D display system enables surgery under low illumination, reducing retinal light exposure compared to conventional microscopes1). This is an important characteristic for reducing the risk of retinal damage due to phototoxicity.
Improved Surgeon Comfort: Surgeon fatigue during long surgeries is reduced, and sustained concentration is expected1).
Comparison of key characteristics between the 3D display system and conventional optical microscopes.
| Characteristic | 3D Display System | Conventional Microscope |
|---|---|---|
| Surgeon Posture | Heads-up (natural posture) | Leaning forward (direct eyepiece view) |
| Light Exposure | Reduced1) | Standard |
| Image processing | Digital enhancement possible | Optical system only |
The 3D display system has been confirmed to show equivalent efficacy to conventional optical microscopes 1). In terms of surgical outcomes (visual recovery and anatomical outcomes), it is not inferior to existing optical microscopes, and it has superior characteristics in ergonomics, light exposure reduction, and digital image enhancement.
The 3D display system can be applied to various ophthalmic surgical procedures.
Cataract surgery: The TrueVision system was developed as a pioneering platform for 3D heads-up cataract surgery. Lens nucleus division, phacoemulsification, and IOL insertion can all be performed under 3D visualization.
Vitreoretinal surgery: This is the field where heads-up surgery is most widely evaluated. In macular hole surgery, the 3D display system has been shown to have equivalent efficacy to conventional microscopes, with reduced retinal light exposure 1). Vitrectomy, membrane peeling, and laser photocoagulation can also be performed under 3D visualization.
Corneal surgery: For DSAEK (Descemet’s stripping automated endothelial keratoplasty), nDSAEK (nanoultrathin DSAEK) has been reported. Ultrathin graft manipulation and air bubble injection can be performed precisely under digital visualization.
Glaucoma surgery: Application to anterior segment surgeries such as trabeculotomy and filtering surgery has also been reported, and the range of applicable procedures is expanding.
Representative 3D display systems currently in practical use are shown below.
NGENUITY
Manufacturer: Alcon
Display: 4K OLED 3D monitor
Stereoscopic method: Polarization method
Features: Designed for vitreoretinal surgery. Optional intraoperative OCT integration. Equipped with digital filter and contrast enhancement functions. Currently the most widely used commercial system.
TrueVision
Manufacturer: TrueVision 3D Surgical
Target surgery: Cataract surgery and anterior segment surgery
Stereoscopic method: Active shutter method
Features: Pioneering platform for heads-up surgery. Early realization of digital 3D visualization in cataract surgery. Also compatible with ORA (intraoperative aberrometry) integration.
Sony HMS-3000MT
Manufacturer: Sony
Type: HMD (Head-Mounted Display) method
Stereoscopic method: HMS (Head-Mounted System)
Features: Provides images to an HMD worn by the surgeon. No monitor required and easily accommodates individual differences. An example of a format that provides an active rather than passive stereoscopic viewing experience.
Compare the specifications of the three main systems.
| System | Resolution | Stereoscopic vision |
|---|---|---|
| NGENUITY | 4K | Polarization method |
| TrueVision | HD to 4K | Active shutter |
| HMS-3000MT | HD | HMD method |
The main technologies incorporated in 3D display systems are described.
HDR (High Dynamic Range) display: Reproduces a wide range of contrast from high to low brightness. It naturally displays the difference between the dark vitreous cavity and bright illumination light, enhancing tissue visibility.
4K to 8K high resolution: The current mainstream is 4K resolution (3840×2160 pixels), and 8K support is under development for the next generation. High resolution improves visibility of the internal limiting membrane and fine retinal structures.
Digital filter: Real-time filter processing can be applied during surgery. Color enhancement, contrast correction, and pseudo-color display of internal limiting membrane staining (e.g., Brilliant Blue G) are available.
Intraoperative OCT integration: Technology that integrates optical coherence tomography (OCT) into the surgical microscope and superimposes tomographic images on the 3D monitor in real time has been developed1). This allows intraoperative confirmation of macular hole closure and evaluation of membrane peeling.
Signal amplification and low-light imaging: By increasing the sensitivity of the camera sensor, high-quality images can be obtained while reducing the amount of illumination light. This is the main mechanism for reducing retinal light exposure.
Stereoscopic vision using a 3D display system generates depth perception by presenting independent images to the left and right eyes. Two main methods are used.
Active stereoscopy (active method): Uses glasses with liquid crystal shutters. The glasses alternately block the left and right lenses at high speed, switching between left-eye and right-eye images frame by frame in synchronization with the monitor. This method is adopted in the TrueVision system.
Passive stereoscopy (passive method): Uses glasses with polarizing filters. The monitor simultaneously displays horizontally and vertically polarized images, and the corresponding polarized glasses separate them for each eye. This method is adopted in the NGENUITY system. The advantage is lightweight glasses that do not require a power source.
HMS (head-mounted) method: Images are displayed directly on an HMD worn by the surgeon. Since images are presented directly in front of the surgeon’s eyes without a monitor, it is easy to adjust to the individual’s interpupillary distance. The Sony HMS-3000MT uses this method.
The camera unit captures light through the beam splitter of the surgical microscope. Images captured by the CMOS sensor are processed in real time and output as 3D video. Minimizing latency is a key issue for maintaining surgical precision, and current systems have reduced it to a level that is not perceptible.
In both the polarizing and shutter methods, latency (video delay) is suppressed to a level that is not easily perceived, and the impact on surgical precision is considered minimal. Additionally, 3D display systems have been confirmed to be as effective as conventional microscopes 1). It is recognized that there is a learning curve during initial introduction as a matter of adaptation.
8K ultra-high resolution: Development of 8K-compatible systems is underway as the next generation beyond current 4K resolution. 8K resolution (7680×4320 pixels) is expected to allow observation of fine structures of the internal limiting membrane and details of retinal blood vessels with greater precision than before.
Development of Head-Mounted Systems (HMS): Improvements continue on HMDs that fully adapt to individual visual characteristics (interpupillary distance, refractive correction). Next-generation HMDs with high brightness and low latency, specialized for surgical use, are in development.
Integration with Augmented Reality (AR): Research is progressing on AR surgical systems that overlay intraoperative OCT images, fluorescence angiography, patient information, etc., onto the surgical video in real time. The goal is to create an environment where the surgeon can access various types of information without looking away.
Heads-Up Application to Slit Lamps: Attempts have been reported to introduce the 3D heads-up method not only to surgical microscopes but also to slit-lamp microscopes used in outpatient examinations. Advantages include improved ergonomics during examinations and easier image recording.
Integration with AI Image Analysis: Development is underway on systems that use artificial intelligence (AI) to analyze real-time video in real time, assisting with tissue identification and dissection. Combination with surgical support robots is also being studied.
As technology costs decrease and clinical evidence accumulates, the adoption of 3D display systems is expanding. Multiple advantages—improved surgeon ergonomics, reduced light exposure, and digital image processing—are recognized, and adoption is increasing especially in large facilities. In the future, integration with intraoperative OCT and AR is expected to advance, evolving into even more high-function platforms.
