Femtosecond laser technology ushers in a new era of cataract surgery
Femtosecond laser technology is gradually revolutionizing refractive surgery, enabling surgeons to create thin LASIK flaps or remove intrastromal tissue rather than perform excimer laser ablation.
This technology has the potential to make similar inroads in cataract surgery, similar to how phacoemulsification supplanted extracapsular cataract extraction 2 decades ago. Some surgeons say they can perform lens fragmentation and create a clear corneal incision, limbal relaxing incisions and anterior capsulorrhexis more safely and accurately with femtosecond lasers than with established incisional and phacoemulsification methods alone.
Femtosecond laser techniques may potentially minimize complications and improve refractive outcomes, experts say.
OSN Refractive Surgery Board Member Stephen G. Slade, MD, who recently performed the first U.S. series of femtosecond cataract procedures with the LenSx laser, is optimistic about the safety and efficacy of femtosecond cataract surgery.
“I’m very enthusiastic on a number of levels,” Dr. Slade said. “I believe that it will improve the safety and efficacy of cataract surgery. I believe it will make cataract surgery more attractive and convenient for patients. And it will improve our outcomes.”
“Even in its early iterations, this technology is very impressive and successfully automates some of the most important steps of cataract surgery: incision creation with or without astigmatic keratotomy, the continuous curvilinear capsulotomy, and sectioning or softening the nucleus,” David F. Chang, MD, OSN Cataract Surgery Board Member, said.
Image: Victor D
Rosa Braga-Mele, MD, FRCSC, OSN Cataract Surgery Section Editor, elucidated the potential for femtosecond laser technology to minimize variations in skill level and subsequent outcomes between surgeons.
“What femto is going to do is level the playing field,” Dr. Braga-Mele said. “It’s going to allow precision and consistency for all surgeons across the board because it will be the machine performing those techniques. It will be easier to train residents and produce more efficient surgeons.”
Three laser platforms
Three femtosecond laser platforms for cataract surgery are currently in various stages of development and regulatory approval.
LenSx Lasers has received FDA 510(k) clearance for use of its femtosecond laser in lens fragmentation, anterior capsulotomy and corneal incision creation.
Dr. Slade cited a study by Hungarian surgeon Zoltan Nagy, MD, in which 60 eyes underwent manual rhexis and 60 eyes had laser rhexis with the LenSx laser. All laser cuts were at the exact diameter attempted, whereas only 10% of the manual cuts achieved diametric accuracy within a tolerance of 0.25 mm.
LensAR has received a foundational U.S. patent that covers intellectual property related to femtosecond laser technology used to increase the flexibility of the crystalline lens to restore accommodation or facilitate lens removal.
The company also recently received 510(k) clearance from the FDA for its laser system to perform anterior capsulotomy in cataract surgery.
Dr. Chang is a medical monitor for clinical trials of the LensAR femtosecond laser, and he has used the LensAR system to perform cataract surgery in Mexico.
OptiMedica has developed a femtosecond laser with a pattern-scanning, ultra-rapid laser and integrated optical coherence tomography imaging.
Refractive cataract surgery
Mark Packer, MD, FACS, said he envisions femtosecond cataract surgery becoming the gold standard because of enhanced safety, accuracy and refractive outcomes.
“I have no doubt that femtosecond phaco is the future of cataract surgery,” Dr. Packer, a member of the LensAR medical advisory board, said. “This is a premium method of performing surgery, which dovetails nicely with the premium IOL technology, presbyopia-correcting lenses.”
As in refractive surgery, femtosecond laser technology is being adapted in cataract surgery to improve safety and visual outcomes, according to William W. Culbertson, MD, chairman of OptiMedica’s cataract medical advisory board.
“It’s basically extending the same precision, dependability and safety of the femtosecond laser to some of the more difficult and imprecisely performed parts of cataract surgery in an attempt to improve safety and visual outcomes,” he said. “It’s taking a laser with its inherent micron precision and coupling it with the dimensional imaging capability of OCT to precisely locate where these laser spots are going to be, and then trying to make these traditionally manually performed parts of cataract surgery much more dependable and complication-free.”
Consequently, femtosecond technology will likely boost the prominence and value of cataract surgery as a refractive procedure, Dr. Culbertson said.
“I think this will have an impact on premium IOLs,” he said. “By virtue of making perfect capsulorrhexes and perfect limbal relaxing incisions, I think it will basically be a refractive tool that is used immediately prior to extraction of the cataract. I believe that eventually it will become something that patients can elect to pay for that is outside the regular third-party reimbursement for cataract surgery because it’s refractive, regardless of whether a premium IOL is involved.”
Femtosecond cataract surgery may also enhance surgical accuracy required for premium IOL implantation, Dr. Chang said, providing a level of precision and consistency that few ophthalmologists can duplicate manually.
“In particular, femtosecond surgery will likely facilitate an increase in implantation of next-generation accommodating IOLs, such as the Synchrony (Abbott Medical Optics),” Dr. Chang said. “Optimal sizing and centration of the capsulotomy are more critical to this dual-optic IOL in order to constrain and control the forward-moving anterior optic.
“The ability to perform a consistently perfect continuous curvilinear capsulotomy and to soften medium nuclei so that they can be aspirated without ultrasound will be very appealing for refractive lens exchange,” he said. “This will be an excellent adjunct to future advances in accommodating IOLs in expanding the popularity and safety of RLE.”
Dr. Slade echoed Dr. Chang’s observations.
“It’s very much a refractive laser,” Dr. Slade said. “To me, that’s what is needed for premium IOL surgery. In other words, patients are … really expecting to have excellent uncorrected vision, so any residual refractive error needs to be dealt with.”
Incisions and lens fragmentation
Above all, femtosecond laser technology enables the surgeon to create precise, reproducible clear corneal incisions and astigmatic relaxing incisions.
Steven G. Slade
“You can say, ‘I’m now doing a 2.8-mm incision positioned 1 mm from the limbus,’” Dr. Slade said. “To me, that’s very exciting to be able to finally do a set that’s reproducible and then come in with a different set and compare that. Plus, of course, you can do corneal relaxing incisions or limbal relaxing incisions that are now of precise depth and precise positioning.”
In femtosecond cataract surgery, lens segmentation and softening involves pre-cutting the lens into four, six or eight pie-shaped or circular segments that after laser softening into small cubes can be aspirated with a 0.9-mm phaco tip. This step reduces or eliminates the need for ultrasound energy to chop nuclear material, Dr. Culbertson said.
“You don’t need to chop these segments if they’ve already been segmented and/or softened by the laser,” he said. “You just push them apart because there’s already a cleavage plane made by the laser down through the lens nucleus. Then, when you push these segments apart and you engage it in the phaco tip, they just blitz in like they’re a much softer cataract … and then you just basically phaco-aspirate it.”
The femtosecond laser reduces phaco time and energy and further enhances intraoperative safety. Shortened intraoperative time results in less endothelial cell loss and reduced risk of complications, including infection, Dr. Culbertson said.
Capsulorrhexis and IOL centration
Surgeons can use a femtosecond laser to make reproducible corneal relaxing incisions and limbal relaxing incisions to correct astigmatism. In addition, the technology will help take the guesswork out of centering the capsulorrhexis and determining effective lens position, Dr. Slade said.
“It’s very much a refractive laser. We know that capsulotomy is a factor in effective lens position. … With this, since we’re able to control the size of the capsulotomy, I believe we’ll have much more constant, reproducible effective lens position,” he said.
The OptiMedica femtosecond laser includes OCT.
“You basically use the OCT to image the entire anterior segment of the eye, including the corneal diameter, corneal thickness, anterior chamber depth and lens thickness,” Dr. Culbertson said.
OCT can also help the surgeon center the capsulorrhexis and determine the effective lens position.
“That’s where a lot of the source of error is,” he said. “We can extrapolate the anterior and posterior curvature of the lens to determine where the recess of the capsular bag is. Even though it’s behind the iris, we can mathematically extrapolate that.”
The LenSx laser also includes a fully integrated, intraoperative OCT for image-guided surgery.
LensAR has developed a customized proprietary measuring and scanning technology based on Scheimpflug principles. It has diagnostic capabilities that enable the characterization and placement of laser cuts in grade 4+ cataracts. To date, grades 4 and 5 cataracts have been treated in clinical studies, according to the company.
Dr. Braga-Mele said she is concerned about femtosecond lasers being used to create a capsulorrhexis in cases with a small pupil.
“I can do a relatively blind capsulorrhexis under a smaller pupil, so I don’t have to stretch a 3-mm pupil to a 5-mm pupil to perform my capsulorrhexis,” Dr. Braga-Mele said. “I just do it underneath the iris as a blind capsulorrhexis. I’m wondering with the femto whether we’re going to have to enlarge all our pupils to a certain size or whether it can create the [capsulorrhexis] underneath the iris as well.”
Dr. Chang, however, noted that the utility of using femtosecond laser technology in challenging cases may be an equally important benefit.
“For many surgeons, the greatest advantage would be improving outcomes with complicated cases, such as performing a [continuous curvilinear capsulotomy] in an eye with very weak zonules or facilitating fragmentation of an extremely dense nucleus,” he said.
Lenticular presbyopia correction
LensAR is undertaking a clinical trial outside the U.S. to determine if its femtosecond laser can be used to soften the crystalline lens for removal or if it can play a part in presbyopia correction, according to Dr. Slade.
“They have done a very good study of the microstructure of the lens, and they believe that they can cut different planes within the lens and make it where the muscles can have more of an effect than they can against an uncut lens,” he said.
Femtosecond presbyopia correction will likely require premarket approval by the FDA, Dr. Slade said.
“I guess the holy grail would be the ability to use the same laser system to either treat presbyopia or to assist in cataract surgery,” Dr. Chang said.
Integration of femtosecond lasers
Questions surrounding the logistics of integrating femtosecond technology into the typical practice abound, Dr. Chang said.
“How to integrate the technology within the operating room will be another interesting challenge,” he said. “It can certainly be used alongside the phaco machine within the OR. However, because the femtosecond steps can be done without creating a full- thickness incision into the eye, another option would be to use the femtosecond laser in a separate room from the OR. Finally, adding more elective options to the procedure will further complicate the patient-clinician decision process, which already encompasses the IOL type and refractive target.”
It is unclear how acquiring a femtosecond laser will affect the typical practice in terms of price, workflow and logistics, Dr. Packer said.
“All of those things will potentially change the delivery of surgery in ways that I don’t think we totally grasp yet,” Dr. Packer said. “For example, the ability of this laser to make incisions and emulsify, or at least break into little pieces, the nucleus without ever violating the ocular surface means that it can be done in a clean environment rather than a sterile environment. So, the laser could potentially be in a separate room. There could be one laser room and two operating rooms, and the patients kind of doing a round-robin between those.”
Dr. Braga-Mele said she thinks femtosecond laser technology will be included in newer-generation phacoemulsification platforms. Combining the two technologies in one platform would enhance economies of scale, reduce costs and resolve logistical issues associated with having two machines, she said.
“Personally, I wouldn’t switch right now because of that,” she said. “However, if phaco technology and newer-generation machines are produced that have the femto technology within the machine and the ability to have one machine even if you have two separate handpieces or whatnot, then that would be much better because it will fit better into an OR, it will smooth out the procedure and it will minimize the amount of time utilized.”
Payment for service
For patients with private health insurance, femtosecond cataract surgery will likely be offered as a premium service, similar to presbyopia-correcting and toric IOLs, Dr. Packer said. However, Medicare billing for femtosecond laser-based services is uncertain.
“I don’t yet grasp how this can be made available to the general population Medicare patients having standard lenses,” Dr. Packer said.
He suggested perhaps integrating the femtosecond cataract surgery fee into the price for premium surgery, “just like we did with the Crystalens (Bausch + Lomb) … the toric lenses, astigmatism correction, wavefront aberrometry, everything else.
“I just don’t see how you do that for a $600 surgeon fee and a $1,000 facility fee,” Dr. Packer said. “Where do you pay for the laser?”
The growing number of patients adopting premium lenses may also have an impact on fees.
Dr. Slade said he thinks that femtosecond laser purchases can fit into the average practice’s financial scheme.
“This is a refractive cataract laser. You will use it for premium IOL patients. If you’re willing to use a laser for LASIK, now we’re talking about something that is 20 times the size of LASIK: cataract surgery,” Dr. Slade said. – by Matt Hasson
- Rosa Braga-Mele, MD, FRCSC, can be reached at 245 Danforth Ave., Suite 200, Toronto, Ontario, Canada M4K 1N2; 416-462-0393; fax: 416-462-3612; e-mail: email@example.com.
- David F. Chang, MD, can be reached at Altos Eye Physicians, 762 Altos Oaks Drive, Suite 1, Los Altos, CA 94024; 650-948-9123; fax: 650-948-0563; e-mail: firstname.lastname@example.org. Dr. Chang is a consultant and medical monitor for LensAR. He is a consultant for AMO.
- William W. Culbertson, MD, can be reached at Bascom Palmer Eye Institute, P.O. Box 016880, Miami, FL 33101-6880; 305-326-6364; e-mail: email@example.com. Dr. Culbertson is a consultant to OptiMedica and AMO.
- Mark Packer, MD, FACS, can be reached at Drs. Fine, Hoffman & Packer, LLC, 1550 Oak St., Suite 5, Eugene, OR 97401; 541-687-2110; fax: 541-484-3883; e-mail: firstname.lastname@example.org. Dr. Packer is on the medical advisory board for LensAR. He is a consultant for Bausch + Lomb and Abbott Medical Optics.
- Stephen G. Slade, MD, can be reached at Slade & Baker Vision, 3900 Essex, Suite 101, Houston, TX 77027; 713-626-5544; fax: 713-626-7744; e-mail: email@example.com. Dr. Slade is the medical director for LenSx and owns shares.