Article Date: 4/1/2008

New Technology Update:

New Technology Update:

Operating microscope represents breakthrough in surgical visualization.

ROCHELLE NATALONI, CONTRIBUTING EDITOR

In retinal surgery, the difference between an operating microscope that provides adequate visualization and one that improves the surgeon's ability to see the delicate structures of the eye's posterior segment can mean the difference between an adequate outcome and a successful outcome. This, of course, is true in anterior segment surgery as well, and along those lines, OPMI Lumera (Figure), a new Carl Zeiss Meditec (CZM; Dublin, Calif.) operating microscope, has quickly gained a following in the United States among anterior segment surgeons who maintain that the device's improved visualization is a "break-through" in ophthalmic surgery. While it is just beginning to attract the attention of retinal surgeons in the United States, the company reports that the Lumera has a devoted following among posterior segment surgeons in Europe and Japan.

AIDING CATARACT SURGERY

"We were already happy with the illumination that we got with our existing operating microscopes, so the improvement that we get with the Lumera is a pleasant surprise," says David Chang, MD, clinical professor of ophthalmology at the University of California, San Francisco. "For cataract surgeons, this new technology improves the red reflex to an impressive degree."

Dr. Chang has been using the Lumera since September, and says it's like watching high-definition television for the first time. "A cataract surgeon will be immediately impressed by seeing much more detail than he or she previously did through other microscopes. The enhanced red reflex and the improvement in contrast is most helpful for seeing microscopic details of the anterior and posterior capsule, the cortex, the endothelial surface, and the anterior vitreous," he explains.

Of course, as Dr. Chang points out, the illumination needs in anterior segment surgery and posterior segment surgery are quite different; however Lumera's technology carries advantages for either region of the eye. The microscope's high optical quality and light intensity enable the surgeon to see the retina in vivid detail, according to Yasuo Tano, MD, chairman of Ophthalmology, Osaka University Medical School, Osaka, Japan.

Figure. The OPMI Lumera

"The Lumera offers a virtually new view of the eye. Not only could I see the fine folds in the posterior lens capsule, I could also easily differentiate the tissues in the posterior segment. Therefore, I use very little light [with this microscope]," says Dr. Tano, adding that, "the high light transmission optics are really unsurpassed."

POSTERIOR POSSIBILITIES

The Lumera's capabilities shine in posterior segment when it is paired with the Zeiss' Visulux motorized fiber slit illuminator, according to Tim Buckley, CZM, marketing manager of Surgical Microscopes & Lasers, Ophthalmology. "This is an ideal illumination system for bimanual retinal surgery. Surgeons tell me the combined technology offers great visualization of membranes and vitreous strands," says Buckley.

According to Kazuo Ichikawa, MD, and Tatsushi Kaga, MD, both the department of Ophthalmology, Social Insurance Chukyo Hospital in Nagoya, Japan, the Visulux slit illuminator (also CZM) is highly useful for several posterior segment applications, including cutting a peripheral vitreous without a vitrectomy lens; imaging of the retinal membrane, anterior membrane and inner limiting membrane; and bimanual vitreous surgery.1

With respect to cutting peripheral vitreous without a vitrectomy lens, Ichikawa and Kaga point out that when only slit illumination is used, the field of vision is narrow, but by combining it with microscope illumination, the field of vision is markedly broadened, which they point out enhances the efficiency of the surgery.

ADVANTAGES FOR THE SURGEON

The Lumera microscope in combination with the Visulux slit illuminator is ideal for observing the retinal membrane, anterior membrane and inner limiting membrane, according to Ichikawa and Kaga, because the combination offers high contrast and superior illumination. Similarly, the combination's broad field of vision and high contrast improve visualization of the extent and height of serous retinal detachment, thereby facilitating neovascular extraction improvements.

Users of the device say that the Visulux is a helpful instrument for membrane peeling, but the fiber slit lamp also simplifies vitrectromies and work on detached retinas and fundus tumors, as well as removal of foreign bodies from the vitreous. In comparison to endo illuminators for retinal surgery, with the Visulux there is less stray light and therefore higher image contrast. Other advantages include no need for a sclerotomy to introduce the illumination into the eye, while procedures on the retinal membrane are possible in the early stages because they are more easily identifiable.

Because the OPMI Lumera has features that are useful for posterior and anterior segment surgery, the device is relevant in a multispecialty practice. This microscope can be combined with any 1 of several floor stands or ceilingmount suspension systems that offer the ability to save settings including starting magnification, focus speed, and defaults for the foot control panel for up to 9 users or applications. There is also a selection of different light sources including single or dual halogen illumination, Superlux Eye xenon illumination, or a combination of both.

Superlux Eye xenon illumination, Buckley explains, enables surgeons to see with fine detail the anatomic structure of the eye in its natural colors. When the microscope is shared, those who prefer halogen can switch to the 'HaMode' filter.

"This new optic enables surgeons who prefer Halogen to immediately switch the light spectrum without any sort of fiber optic exchange," explains Buckley. The Visulux slit illuminator can be used with the Superlux Eye xenon illuminator for microscopic illumination. Choosing the "combination" light system enables the surgeon to concurrently illuminate, using both the microscope's illumination system and an external accessory such as the Visulux.

FEATURES FURTHER ITS VALUE

Another Lumera feature is the Invertertube, which the company says answers the ergonomic needs of the busy surgery practice. The optional Invertertube enables the operator to switch between cataract and retinal procedures with no conversion. "Retinal physicians often have a huge stack of accessories on their microscope: biom, laser filters, beam splitter, camera, inverter, etc.," says Buckley. "The Zeiss Invertertube is completely integrated within the binocular, which enables the surgeon and assistant to move about more comfortably when using the Zeiss microscope."

Stereo Coaxial Illumination (SCI) is the primary feature that differentiates the Lumera from other operating microscopes, according to Dr. Chang. "The red reflex is so bright, that it almost seems like there is a tiny light bulb inside the eye — like a jack o'lantern," he says. "With the new illumination system, our Zeiss optical engineers also had the freedom to then take the optic design to a new level. Therefore, in addition to homogenous red reflex, the physician will experience increased contrast, depth of focus, and unique detail recognition," explains Buckley.

Lumera Operating Microscope Specs
Surgical microscope
• Apochromatic optics
• Motorized zoom system, 1:6 zoom ratio, magnification factors = 0.4 to 2.4
• Focusing range: 50 mm
• Binocular tube: 0-180° tiltable tube (optional Invertertube)
• Eyepieces: 10x (12.5× optional)
• Objective lens f=200 mm (f=175 mm optional)
• DeepView: depth of field management system

Illumination
• Adjustable SCI red reflex illumination and surrounding field illumination
• Integrated 408 nm UV barrier filter
• Swing-in GG475 filter to reduce blue ratio
• Retinal protection device
• Fiber optic illumination
• Optional: fluorescence filter

Light source
• Superlux Eye xenon illumination with manual bulb change, including HaMode filter
• Optional: 12V, 100 W halogen illumination with automatic bulb change
• X-Y coupling - 40 mm × 40 mm adjustment range
• Button for starting positions of the X-Y coupling and focus
• 13.7 kg (30.2 lb) with Invertertube integrated assistant's microscope, objective lens and eyepieces

Suspension systems
• S88 floor stand
• S8 ceiling mount with lifting column
• S81 ceiling mount with rigid column
• Maximum load capacity: 20 kg (44.1 lb) (complete microscope equipment, including accessories)

Source: Zeiss.com

With SCI, the primary illumination is split into 2 beams that separately follow the optical path of each individual ocular. The resulting stereo coaxial illumination produces an intense red reflex, according to Buckley. "The optics have been re-engineered to provide better contrast, which maintains and improves the depth perception," he explains. The result of this is unique detail recognition, high-contrast brilliance and stability of the red reflex — even with strongly pigmented, decentered, and ametropic eyes, according to Buckley.

With the advanced depth perception provided by SCI, surgeons can see the complete anterior and posterior segment physiology and clearly see details such as the cornea epithelium and fine folds in the posterior lens capsule. The surgical field viewed in the microscope can be transmitted to an integrated LCD flat screen, which gives the entire surgical team a reliable source of information throughout the procedure. "With the increasing popularity of online video sharing, techniques from across the globe are more easily shared," says Buckley.

The Lumera's integrated assistant's microscope is an optional feature. The second surgeon selects the focus and magnification independent of the main surgeon, which enables active assistance. The assistant is afforded a full 3-D quality image without limiting the main surgeon's light.

Magnetic brakes simplify positioning the Lumera. "The system smoothly glides into a new position; when locked, the microscope remains firmly in place," says Buckley. The brakes for the XY and Z directions can be released separately. "This," says Buckley, "provides the surgeon with even more comfort for minor positioning changes."

DELIVERING SURGICAL ADVANTAGES

With or without the optional bells and whistles, Dr. Chang points out, the Lumera provides excellent visualization for anterior segment surgeons. "The improvement in contrast and red reflex intensity means that we can see more with less light delivered to the eye," he adds. "Aside from the aesthetics, the improved visualization is great in complicated cases — such as with small pupils or denser lenses. All cataract surgeons are looking for any kind of an edge with these difficult cases, and the Lumera delivers in this regard." RP

REFERENCE

1. Ichikawa K, Kaga T. Insight, Carl Zeiss newsletter, Volume 4; Sept. 2002



Retinal Physician, Issue: April 2008