April 2016

 

COVER FEATURE

 

Femto in cataract surgery: The state of the technology


by Liz Hillman EyeWorld Staff Writer

 
 

I advise my residents to always use the tools of evidence-based medicine that we all learn throughout medical school.

Having said that, always keep an open mind because when things are new, sometimes we dont know what role they will eventually play in our practices. Saras Ramanathan, MD

 
use the femtosecond laser

Dr. Ramanathan teaches resident Chris Aderman how to use the femtosecond laser to create corneal incisions and capsulorhexis in a patient at UCSF Medical Center.

Source: UCSF

With FLACS still in its infancy, physicians discuss the research, bringing it to practice, and education

The femtosecond laser is not the first and its certainly not the last of new technologies that could revolutionize the way physicians perform cataract surgery. But the jury is still out on whether the technologyapproved by the U.S. Food and Drug Administration for this purpose in 2010trumps traditional cataract surgery technique. Within the last decade, hundreds of studies involving femtosecond laser-assisted cataract surgery (FLACS) have been published, with more to come. So what does the current research have to say? How are physicians currently bringing it into their practice? And how is it being introduced to residents? I think ophthalmology in general is still trying to grapple with how we optimize the usefulness of the femtosecond laser in our practices, said Saras Ramanathan, MD, associate professor of ophthalmology, University of California, San Francisco (UCSF) School of Medicine. Ophthalmologists in this country are still trying to figure out how the femtosecond laser fits into their practiceswe dont all agree.

All eyes on the data

A study of 4,000 cases from a single center in Tasmania published in 2015 in the Journal of Cataract & Refractive Surgery found that both FLACS and traditional cataract surgery were safe and had low intraoperative complications that could affect refractive outcomes and patient satisfaction.1 A 6-month follow-up study comparing the outcomes of FLACS and manual phaco surgery by Yu et al. published in December 2015 in Clinical & Experimental Ophthalmology found similar safety and efficacy between both procedures.2 A separate 6-month follow-up study published in July 2015 in the Journal of Cataract & Refractive Surgery compared visual recovery and refractive stability between the 2 procedures and found that FLACS resulted in faster visual recoveries and more stable refractive results, compared to manual cataract surgery.3 As for visual acuity, a literature review published in Current Opinion in Ophthalmology in January 2014 found that most but not all existing studies showed no statistically significant difference in visual acuity and mean absolute refractive error between laser and conventional cataract surgery cases.4

There was also a 2013 review published in Eye, the journal of the Royal College of Ophthalmologists, that cited several studies that concluded femtosecond laser use was significantly more accurate in terms of creating a reproducible capsulotomy compared to manual capsulorhexes.5

Stephen McLeod, MD, chair, Department of Ophthalmology, UCSF, pointed out that the current FDA-approved femtosecond laser platforms for use in cataract surgery are still in their first iteration, however sophisticated they might be. Given that femto can at least compete with the high standards of manual modern phacoemulsification is impressive, he said, but the technology is still in its infancy.

It does say a great deal, however, that a radically different approach to some of the key elements of a procedure where the current standard has evolved over decades of refinement and sequential improvements in instrumentation and techniques can compete at such an early stage, Dr. McLeod said. The big picture opportunities for improvement in FLACS, Dr. McLeod added, include cost, speed, and efficiency, but he noted what he thinks are some clear benefits of using the laser at least for some specific parts of the procedure. In terms of reproducibility and predictability of the size and centration of the capsulorhexis, the femtosecond laser seems to win out over manual capsulorhexis creation, he said, adding that he has been extremely impressed with the capsulorhexis edge in the months following surgery, preventing uneven capsular contraction. Its the lasers consistency of the edge of the capsulorhexis that could pose a problem though. Dr. McLeod explained its potential to skip areas and create tags, saying this intrinsic postage stamp quality could increase the risk for anterior capsule tear. Dr. McLeod said conventional phaco surgery still outperforms femto when it comes to cost, efficiency, overall energy delivery to the eye, greater capsulorhexis integrity, and easier cortical cleanup. Conventional methods are also preferred in patients with small pupils. Dr. McLeod further explained his stance on the energy delivery of the 2 methods. The now established conventional wisdom is that with the femtosecond laser, you are able to reduce energy delivery to the eye, he said. However, that is specific to the reduced phaco energy. The total energy delivered to the eye actually comprises both femtosecond laser energy and phaco energy. We have to account for additional femtosecond energy that has been delivered to the eye for the capsulorhexis that in standard phaco is achieved mechanically, as well as the femtosecond energy that has been delivered for the lens cleavage. As for the laser making fragmentation easier, Dr. McLeod said that is a benefit, especially for surgeons who are less comfortable with energy-reducing phaco chopping techniques. This can also enhance patient safety in cases of loose zonules because the lens is disassembled with less effort, which can reduce zonular stress and risk of zonular dehiscence, he said.

Bringing femto to practice

Once physicians decide to bring the femtosecond laser into their practices for cataract surgery, they have to prepare to talk about it with patients. As the ASCRS Refractive Cataract Surgery Subcommittee said in a 2013 article, providers have a tremendous responsibility in informing patients of their options as femto vs. manual brings with it technical, ethical, and financial challenges.6

We are only beginning to comprehend the benefits and complexities of this exciting new technology, the subcommittee wrote. In addition to physicians introducing patients to FLACS, sometimes it is the patient who brings up the option.

Some patients have researched the femtosecond laser and request this by name during cataract evaluation, said Cynthia Chiu, MD, associate professor, UCSF, adding that she only offers it in combination with premium intraocular lens use or for corneal astigmatism correction. Due to direct imaging of the cornea, the femtosecond laser can create intrastromal AK incisions with precision in the depth of treatment. Studies are starting to report the improvement in uncorrected visual acuity using femtosecond lasers due to the reduction of the corneal cylinder. Even patients receiving monofocal IOLs can benefit from astigmatism correction because many surgeons do not offer toric IOLs below a cylinder of 1.5 D, she said.

Dr. Chiu said she has always been comfortable discussing premium cataract services with her patients, even prior to femtosecond laser options. It has become a more common discussion now that lower amounts of corneal astigmatism can be well-treated at the time of the surgery, she said. A possible negative to FLACS at the practice level could include longer operating times. Dr. Chiu said it only adds about 5 minutes to her manual phaco time at a dedicated ophthalmic ambulatory surgery center. At UCSF, where there are more regulations for the university operating room compared to private practice, Dr. Chiu said the femto laser has added about 20 minutes to operating times. The cost of the femtosecond laser to achieve refractive outcomes, such as astigmatism correction at the time of cataract surgery, is not covered by Medicare or private insurance. Thus, patients must be counseled and consent to paying for this additional charge out of pocket.

Resident programs and FLACS

If established physicians are still figuring out how FLACS may or may not fit into their practice, what then is the responsibility of educators training the next generation of ophthalmologists? Dr. Ramanathan admitted she is still deciding how she feels about FLACS compared to traditional methods based on outcome data but thinks there is a responsibility to teach the new technology nonetheless. I dont know exactly how much femtosecond laser cataract surgery Im going to be doing 5 years from now, but I suspect that this is the direction our field is moving; just as a lot of people were late to the phacoemulsification party and regretted it, I think we cant be late to the femto party, she said. We have to see where this technology is going. There are going to be numerous iterations to what were doing, but Id rather become comfortable with the technology now and let my residents become comfortable with it, so that the learning curve for them is not so steep later. As for when to start FLACS education for residents, Dr. Ramanathan said they need to be comfortable with phaco first, otherwise they would not be able to handle complications that could occur with femto. Furthermore, some aspects of femtosecond surgery could make the later phaco portion more difficult, such as in cortical cleanup. Overall, Dr. Ramanathan encourages her residents to be cautiously enthusiastic with femto and with other new technologies that will come down the pike.

I advise my residents to always use the tools of evidence-based medicine that we all learn throughout medical school, she said. Having said that, always keep an open mind because when things are new, sometimes we dont know what role they will eventually play in our practices. We always have to walk a line of being not too ready to adopt something just because its new, but not too late to adopt something when its been shown to be beneficial. Divya Srikumaran, MD, assistant professor of ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, said that while residents should be aware of the newest technologies, they need to have a very healthy sense of the appropriateness of them. Sometimes its easy to get carried away with what is perceived as the latest and greatest, she said. You should have a healthy amount of skepticism as to whether its really better and challenge all your trainees to make sure they are exploring that with every new technology before they incorporate it into their practice; we have to model that with our behavior as well as in our teaching practices. So where are we now? Standard phaco and femtosecond cataract surgery have evolved to the point that if done well in experienced hands, both will have excellent outcomes, Dr. McLeod said. However, femtosecond cataract surgery is in its infancy, so its trajectory likely far outpaces that of phaco, and so in the interest of collectively advancing technology and options for our patients, it serves us well to responsibly apply this new platform and help to move it forward.

References

Femto in surgery article summary

1. Abell RG, et al. Femtosecond laser-assisted cataract surgery versus standard phacoemulsification cataract surgery: outcomes and safety in more than 4,000 cases at a single center. J Cataract Refract Surg. 2015;41:4752.

2. Yu Y, et al. Comparative outcomes of femtosecond laser-assisted cataract surgery and manual phacoemulsification: a six-month follow-up. Clin Experiment Ophthalmol. 2015 Dec 30.

3. Conrad-Hengerer I, et al. Comparison of visual recovery and refractive stability between femtosecond laser-assisted cataract surgery and standard phacoemulsification: six-month follow-up. J Cataract Refract Surg. 2015;41:135664.

4. Chen H, et al. Visual and refractive outcomes of laser cataract surgery. Curr Opin Ophthalmol. 2014;25:4953.

5. Trikha S, et al. The journey to femtosecond laser-assisted cataract surgery: new beginnings or a false dawn? Eye. 2013;27:46173.

6. Donaldson KE, et al. Femtosecond laser-assisted cataract surgery. J Cataract Refract Surg. 2013;39:175463.

Editors note: The physicians have no financial interests related to their comments.

Contact information

Chiu: Cynthia.Chiu@ucsf.edu
McLeod: Stephen.McLeod@ucsf.edu
Ramanathan: saras.ramanathan@gmail.com
Srikumaran: dsrikum1@jhmi.edu

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