April 2008

 

OPHTHALMOLOGY NEWS

 

A better view with the Lumera


by Maxine Lipner Senior EyeWorld Contributing Editor

   

New microscope enhances clarity in the eye

Image of the ReStor multifocal lens taken through the Lumera microscope

View of retained ophthalmic viscosurgical device (Amvisc Plus, Bausch & Lomb) through the Lumera microscope Source: David F. Chang, M.D.

Very little has changed with operating microscope technology in recent years—but 2008 is different. Operating with the new OPMI Lumera (Carl Zeiss Meditec, Jena, Germany/Dublin, Calif.) is akin to watching high definition television for the first time, according to David F. Chang, M.D., clinical professor, University of California, San Francisco. “It just strikes you ... that ‘Wow, I didn’t think that things could look this clear,’” Dr. Chang said. “Virtually all of the surgeons at our facility have had this reaction when they first used this microscope. It’s that obvious and impressive.”

Gaining the “jack o’lantern” effect

There are several new features that contribute to the improved visualization with this microscope, primarily stemming from enhancements in illumination, according to Dr. Chang. Like all operating microscopes, the Lumera tries to optimize the red reflex. “A bright red reflex is necessary to see the cortex, details in the capsule, and certain details of the cornea,” Dr. Chang said. “So the question has always been, how do you maximize the red reflex with a surgical microscope?”

With the office slitlamp, the red reflex is created with zero-degree retroillumination, when the ophthalmologist is looking coaxially through the same optical path as the illumination beam. “With zero-degree slitlamp retroillumination, however, we lose our ability to judge depth,” Dr. Chang said. “Therefore, surgical microscopes have had to cheat a little bit by having the illumination beam enter at a 2-degree angle. This compromise still gives us the bright backscatter of light but at least preserves more contrast and depth perception.”

The Lumera, however, uses an entirely new approach. “What Zeiss does with the Lumera is split the main illumination beam and align each of the resulting two beams directly along the path of the surgeon’s two oculars,” Dr. Chang said. “Now, each of your two oculars has its own dedicated coaxial illumination beam, which dramatically improves the red reflex.” Zeiss had to re-engineer the optics to preserve depth perception by improving the contrast, according to Dr. Chang. “We finally can have zero-degree retroillumination without sacrificing our depth of field.” With the Lumera, practitioners also have a choice of traditional Halogen or the newer Xenon illumination. “This is the first microscope to give us a choice of illumination systems that is interchangeable,” Dr. Chang said. He explains that the Xenon illumination appears much whiter, while the Halogen light is yellower by comparison. “The Xenon illumination also really seems to improve the contrast,” Dr. Chang said. A third oblique 6-degree illumination beam is used to optimize visualization of the ocular surface and the chopped nuclear fragments. “This oblique beam has a separate adjustment control that allows it to be dimmed when the surgeon wants an even brighter red reflex, analogous to when surgeons turn off the OR room lights,” he explained. In concert, all these new optical features work together to heighten surgical visualization, Dr. Chang finds. “The brighter red reflex and improvement in contrast allows us to see greater details within the cataractous lens and at the level of the anterior and posterior capsule,” he said. Dr. Chang has nicknamed it the “jack o’lantern” red reflex. “It’s almost like a tiny light bulb inside the eye glowing from within,” he said. “That’s how bright it is, like a jack o’lantern with a candle inside.”

Aiding complex cases

What are the clinical benefits of this high definition surgical view? “The Lumera improves our ability to visualize any structure that we normally require the red reflex to see,” Dr. Chang said. The surgical steps in question would be the capsulorhexis, cortical cleanup, capsular polishing, and IOL insertion. “It’s also really good for seeing fluid interfaces, such as intracameral injections and the presence of residual viscoelastic in the eye,” Dr Chang said. However, Dr. Chang finds the Lumera to be most valuable when surgical difficulties are encountered. “Anytime something is starting to go wrong, this is when we really need to see the anterior and posterior capsule as well as possible,” he said. “If you’re struggling with the capsulorhexis, or if you think there might be a zonular dialysis or a tear in the posterior capsule, what do we always do? We increase the illumination brightness to try to get a better view,” Dr. Chang explained. “The other situations where we do this are when the red reflex is poor, such as with smaller pupils, a dense nucleus, or poor corneal clarity,” he added. “These are all cases where the Lumera will give surgeons more of an edge.” When it comes to chopping and emulsifying the nucleus, practitioners likely will not see any particular advantage to the Lumera. “We ordinarily lose the red reflex during emulsification of moderate to dense nuclei.” Dr. Chang said. “However, seeing cortex, posterior capsular debris, and the location of the IOL will be enhanced by a better red reflex.” Overall, Dr. Chang believes that surgeons will favor the enhanced visual quality that the Lumera has to offer. “I think that the Lumera would be particularly advantageous for residents,” he noted. “In addition to the optimized surgical view, there is an enhanced assistant scope that has a true stereo view.” Dr. Chang reasons that surgeons won’t want to purchase more expensive technology just to get a prettier picture. “However, we are always looking for that extra edge when we deal with difficult cases, and this may be more of a justification for the higher cost,” he said. “Just like with high definition television, after you try it, there is a bit of a letdown when you return to your former viewing system.”

Editors’ note: Dr. Chang has no financial interests related to his comments.

Contact Information

Chang: 650-948-9123, dceye@earthlink.net

A better view with the Lumera A better view with the Lumera
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