Device focus
Laser systems for refractive cataract surgery

This month's column discusses the latest in "femto for phaco"

The latest phaco device innovation to come to market or be in development is the advent of the femtosecond laser for refractive cataract surgery. Podium presentations have touted the ability of the lasers to create more precise incisions and capsulorhexis, but a hefty price tag and no long-term data (yet) have continued the debate.
With these devices estimated to cost anywhere from $400,000 to $550,000 and service fees after the first year expected to be about 10% of the purchase price, Jonathan H. Talamo, M.D., associate clinical professor of ophthalmology, Harvard Medical School, Boston, said relevant indications and regulatory approvals may be crucial for both manufacturers and those debating which system to purchase. Alcon's LenSx (Fort Worth, Texas) has regulatory clearance in the U.S. for capsulotomy, lens fragmentation, relaxing incisions, and cataract incisions. The LensAR system (Winter Park, Fla.) and Catalys (OptiMedica, Santa Clara, Calif.) have approval for capsulotomy and lens fragmentation. Victus (Bausch + Lomb/Technolas, Rochester, N.Y./Munich) does not yet have any U.S. regulatory approvals. In Europe, Victus has received the CE mark for LASIK flap, astigmatic keratotomy, INTRACOR, capsulotomy, and lens fragmentation.
At the 2011 American Academy of Ophthalmology (AAO) meeting, William W. Culbertson, M.D., professor of ophthalmology, Bascom Palmer Eye Institute, Miami, said during a press conference on the topic that ultrasound energy use "was reduced by 45% in the laser pre-treated eyes compared with the eyes receiving standard phaco. Also, surgical manipulation of the eye was reduced by 45% in eyes that received laser pre-treatment as compared to manual standard surgery."
As noted in Table 1, there are significant differences among the devices, namely in the areas of docking strategies, imaging, and ergonomics, Dr. Talamo said. Below, EyeWorld provides a brief synopsis of the lasers from various presentations (podium and otherwise) during the 2011 AAO meeting.

Catalys

Barry Seibel, M.D., Seibel Vision Surgery, Los Angeles, said compared with manual techniques, "we had a tenfold decrease in deviation from intended diameter" by using the Catalys. He presented results from a 29-patient study, where one eye was treated with the Catalys for capsulotomy and lens fragmentation and the other eye was treated manually.
The system's liquid optics interface also allows for optimal lens pre-fragmentation, he said. "Because there is no corneal distortion, the intraocular pressure rise is minimal," he said, which allows for "both precise optical coherence tomography (OCT) imaging and accurate, predictable, and energy-efficient laser delivery."

LensAR

Louis D. "Skip" Nichamin, M.D., Laurel Eye Clinic, Brookville, Pa., said a major benefit of the LensAR system is its "proprietary imaging; it's not OCT but 3D-confocal structured illumination." Advantages to this type of imaging are its ability to provide a three-dimensional reconstruction of the anterior ocular structures through ray tracing while providing biometric data, including corneal, anterior chamber, and lens metrics, he said. Mark Packer, M.D., clinical associate professor, Oregon Health & Sciences University, Portland, Ore., found that when the LensAR lens fragmentation was used in 225 eyes, there was no loss of endothelial cells, while 63 eyes that received standard treatment had cell loss of 1-7%. Differences were statistically significant at the 90% level for grades 1 and 3, but not grades 2 and 4, he said.

LenSx

Jorge L. Alio, M.D., professor and chair of ophthalmology, Miguel Hernandez University, Alicante, Spain, described his technique of sub-1 mm incisions, a process he dubbed "Femto-MICS." A prospective study evaluated the reproducibility and refractive impact of corneal incisions made with the LenSx for both standard and micro-incisional surgery; the incision width was between 1 and 1.3 mm, with follow-up at 1 month. "The incisions are always self-sealing and induce no refractive astigmatic change," he said. His group found "the best optical profile is obtained with two 1-mm incisions, orthogonal, with a third incision at 1.8 mm" (opened for the purpose of IOL implantation).
Zoltan Nagy, M.D., clinical professor of ophthalmology, Semmelweis University, Budapest, Hungary, found a laser two-plane incision (n=42) does not require stromal hydration, but a manual incision (n=43) needs stromal hydration 90% of the time. Globally comparing the 6,000+ procedures performed with the LenSx, more patients reached 20/20 earlier in the post-op period with the laser than through manual techniques. The laser is "more predictable at month 1 with a 78% reduction in pre-existing cylinder." Surgically induced astigmatism was lower with the laser as well, "which may ultimately improve the accuracy of limbal relaxing incisions and toric calculators," he said.
Table 1. Key system figures for the femtosecond lasers for refractive cataract surgery Source: Jonathan H. Talamo, M.D.

Victus

Gerd Auffarth, M.D., department of ophthalmology, University of Heidelberg, Germany, said when the laser gets approved in Europe and the U.S., "it will be the first platform to offer both cataract and refractive procedures," noting it can create a LASIK flap and can be used in keratoplasty, corneal crosslinking, and astigmatic keratotomy as well as cataract. Further, the system's curved interface means surgeons are inducing less pressure on the cornea, he said. His initial case series of seven eyes with black or brunescent cataract (some with pseudoexfoliation as well) resulted in 20/20 outcomes and no cases of capsule rupture.
Michael C. Knorz, M.D., medical director, FreeVis LASIK Center, Mannheim, Germany, said the laser also "had an edge" over manual astigmatism correction because "multifocal IOLs will not tolerate any astigmatism greater than 0.5 D. The only limitation is that the pupil must be large enough to expose what you would like to laser." EW

Editors' note: Dr. Alio has financial interests with Alcon. Dr. Auffarth has financial interests with Technolas. Dr. Culbertson has financial interests with OptiMedica. Dr. Knorz has no financial interests related to this article. Dr. Nagy has financial interests with Alcon. Dr. Nichamin has financial interests with LensAR. Dr. Seibel has financial interests with OptiMedica. Dr. Talamo has financial interests with Alcon, B+L, and OptiMedica. EyeWorld Staff Writers Faith Hayden and Jena Passut assisted with this article.

Contact information

Alio: jlalio@vissum.com
Auffarth: gerd.auffarth@med.uni-heidelberg.de
Culbertson: w.culbertson@miami.edu
Knorz: knorz@eyes.de
Nagy: nz@szem1.sote.hu
Nichamin: nichamin@laureleye.com
Seibel: idoc2020@me.com
Talamo: jtalamo@lasikofboston.com