Fast progression seen in launch of femtosecond laser-assisted refractive cataract surgery

Issue: May 25, 2012

Any significant change in technique or technology applied to cataract surgery is guaranteed to generate significant interest and controversy. This is due to the fact that cataract surgery remains by far the most common surgical procedure performed by ophthalmologists, with about 3.3 million procedures a year in the U.S. and 19 million globally, according to Market Scope. It is therefore no contest that the bread-and-butter surgical procedure in ophthalmology worldwide is cataract surgery, usually combined with IOL implantation.

In refractive corneal surgery, the femtosecond laser in combination with the excimer laser, now just 10 years from initial commercialization, dominates market share in advanced countries for the correction of refractive errors. So, the femtosecond laser and its capabilities are very familiar to the LASIK surgeon. For the less familiar cataract surgeon, the femtosecond laser is a computer-programmable laser scalpel that can make exquisitely precise and reproducible incisions in relatively transparent tissues. The first lasers applicable to cataract surgery were commercialized just 1 year ago, so it is timely to review their impact to date.

First, to assure transparency, I would like to disclose that I was an early consultant for LensAR and remain a consultant for Alcon, AMO and Bausch + Lomb, all of which are active in the femtosecond laser field. My practice, Minnesota Eye Consultants, actively utilizes several femtosecond lasers routinely, including the Alcon LenSx laser in cataract surgery and the AMO FS60 and iFS in corneal surgery.

Richard L. Lindstrom

We have used these lasers for keratoplasty and to generate precise LASIK flaps and arcuate keratotomy in refractive corneal surgery and to create the capsulorrhexis, corneal relaxing incisions, nuclear fragmentation, and the primary and secondary incisions in refractive cataract surgery. We currently do 100% of our LASIK cases with the femtosecond laser, as even with very experienced and high-volume surgeons, we have found superior efficacy and safety. While the experience is smaller and shorter with the femtosecond laser in cataract surgery, my impression at this early stage of development and commercialization is even more positive than it was in the early days of femtosecond laser-assisted LASIK.

The femtosecond laser creates a capsulorrhexis that is round, perfectly sized, centered at the surgeon’s discretion and robust to anterior capsular tears. In early studies, effective lens position outcomes are tighter, generating better defocus outcomes. I do supracapsular phacoemulsification, which requires hydrodissection and tilting of the nucleus prior to nuclear removal. My incidence of anterior rim tear to date is zero. I also have no posterior capsule tears or vitreous loss. Using gentle pulsatile hydrodissection, I have experienced no cases of capsular block syndrome. The pupil often constricts some after capsulorrhexis, but dilute methylparaben-free epinephrine or phenylephrine in non-preserved lidocaine injected intracamerally at the beginning of the case reliably enlarges the pupil. Cortex removal requires a more centripetal stripping but is easily learned. Nuclear fragmentation and softening can reduce ultrasound time and power, and technique development is progressing rapidly. Primary and secondary incisions are reproducible from one surgeon to another and from one case to another. Most wounds still require hydration for good sealing, similar to what I use routinely in my diamond keratome incisions. As our case volume and surgeon experience grow and knowledge is shared among the nearly 1,000 surgeons who are using the femtosecond laser for cataract surgery worldwide, ideal incision design and dimensions will further evolve.

Most exciting to me, because it is a career-long interest, astigmatism correction with a corneal or limbal relaxing incision is proving to be a powerful, reproducible, consistent, customizable and titratable treatment, far better than anything I have experienced before. The primary goal of femtosecond laser-assisted refractive cataract surgery in my practice is to enhance refractive outcomes. To me, the goal for the refractive cataract surgeon by 2020 is to achieve LASIK-like outcomes for our cataract patients who have a lifestyle-enhancing refractive outcome goal. To do this, we must manage astigmatism and defocus to within 0.5 D of target. My femtosecond laser-assisted LASIK patients achieve 20/20 or better in more than 90% of cases with a single procedure, and my enhancement rate is less than 3%. My historical control in refractive cataract surgery is closer to 60%, with an enhancement rate of 20%.

I am driven to do better, and since applying the combination of intraoperative keratoscopy to more accurately mark the steep and flat meridians, the femtosecond laser to customize capsulorrhexis and corneal incisions, and intraoperative aberrometry to measure my outcomes during surgery, I am approaching that goal. In a recent consecutive series of 25 patients, I was able to achieve a refractive outcome within 0.5 D of target for defocus and astigmatism in 92% of cases. No patients in this group have yet required enhancements, and patient satisfaction is very high. Further data collection and planning software are under active development, and progress is occurring exponentially.

In closing, a few thoughts about the economics. I do not charge any additional fee for simply using the femtosecond laser. I use it in some patients who do not have a lifestyle-enhancing refractive outcome goal, at no additional cost to the patient, when I think it is in the patient’s best interests. We are still learning when and where the capabilities of the femtosecond laser might be expected to enhance surgery safety and reduce complications. Cases with weak zonules or sectors of absent zonules, hypermature and white cataracts, and Fuchs’ dystrophy may represent pertinent examples.

I primarily use the femtosecond laser in those patients who have a lifestyle-enhancing refractive outcome goal to treat and manage astigmatism through incision customization. The more reproducible effective lens position, potentially better IOL centration and absence of optic tilt also promise to offer additional benefits that may enhance the performance of toric and multifocal IOLs. Together, in the patient seeking a specific lifestyle-enhancing refractive outcome goal, it is a win for the patient and the surgeon to reduce the incidence of enhancements.

Economically, the technology requires a reasonable volume of patients seeking a refractive outcome goal that requires astigmatism management. This for me includes multifocal, accommodating and toric IOLs, as astigmatism severely degrades the performance of these IOLs. While I have managed many patients with residual refractive error after presbyopia-correcting IOL implantation with LASIK or PRK enhancements, these procedures are not without problems in the elderly patient with ocular surface disease, and every patient would prefer a single procedure to achieve their quality-of-life goals. In our practice, growth in overall cataract surgery and refractive cataract surgery volume driven by enhanced postoperative outcomes has been the major driver of economic viability for the femtosecond laser in both refractive corneal and refractive cataract surgery.

Nearly 30 years ago when I adopted manual refractive cataract surgery techniques and technologies, my primary goal was the same as today, to generate highly satisfied patients by enhancing their refractive outcomes and uncorrected no-glasses vision. Highly satisfied patients whose expectations are met or exceeded send their friends and family for surgery. Patient word-of-mouth referral based on surgical excellence is a great engine for practice growth. The femtosecond laser has already proved its worth to my practice, and many other early adopter surgeons are also reporting strong cataract volume growth after adding this technology to their practice.

I firmly believe that femtosecond laser adoption in refractive cataract surgery will mimic that experience in refractive corneal surgery. If so, the femtosecond laser will join the long list of disruptive technologies in cataract surgery, such as phacoemulsification, posterior chamber IOLs and viscoelastics, that truly changed how we do lens-based surgery and, in some settings, which surgeon does the surgery. We will know for sure by 2020, but I experienced firsthand the adoption of femtosecond lasers in refractive corneal surgery, and we are progressing faster in the femtosecond-assisted refractive cataract surgery launch.