I really don’t understand why I need to justify the clear benefits of using a laser to perform a large percentage of my surgery. After all, the laser offers a level of precision beyond the capabilities of human surgical skill. And while I can certainly understand why there is a debate about justifying the finances of femtosecond laser-assisted cataract surgery (FLACS), it is hard to deny the increased precision and ability to perform less invasive cataract surgery with the use of the femtosecond laser.1 In addition, it is a tool that makes my surgery much easier.
Being employed in academics for 20 years, admittedly I am buffered from the cost aspect of FLACS, but I think very few surgeons would decline the use of a tool that makes any aspect of our lives easier ... unless we had to pay a significant penalty for the use of that tool.
The femtosecond cataract surgery debate has been ongoing since around 2010 when the FDA approved FLACS. In this article, I will do my best to separate the clinical benefits from the ongoing financial debate that often clouds this issue.
ABOUT THOSE STUDIES …
I understand that the results of some large studies have not supported significant benefits to visual outcomes or safety of cataract surgery in the hands of some of the best cataract surgeons in both Europe and the United States.2,3 The difficulty with interpreting these studies partially stems from our surgical proficiency and excellent outcomes with traditional cataract surgery. If the reference point is a mild but visually significant nuclear sclerotic cataract in a perfectly healthy eye, we know that surgery will most likely lead to excellent vision with rapid visual recovery when measured by Snellen acuity and presence or absence of complications (as are the end points in these large studies).
However, I challenge that the same surgery could be performed using less energy, with a more precisely sized and centered capsulotomy, potentially with a small limbal relaxing incision that could theoretically make the surgery better, even if not yielding a measurable difference in these large studies. In more challenging cases, such differences may be more significant (See “FLACS for challenging cases”).4,5
SIMPLIFYING CASES FOR EXPERIENCED AND NEW SURGEONS
When I sit down to begin my cataract surgery after the femtosecond laser has already created my capsulotomy and my lens has been pre-fragmented, I feel as if half the work has already been done. Certainly, if there were no cost difference, I would love to walk into every case at that point — the femtosecond laser makes my job easier, especially in the most difficult of cases.
Similarly, in the hands of residents or potentially less proficient surgeons, I can certainly see the utility of having a large percentage of the work pre-designed and executed to near perfection. This has been supported in the literature through studies on the learning curve of residents performing their first cases of cataract surgery.6 Even in the hands of the average or exceptional surgeon, evidence shows improved efficacy by reducing phaco energy by more than 50% to 99%.7-10
FLACS is also very helpful to less experienced surgeons in the area of astigmatism correction during cataract surgery. Undeniably, astigmatism correction during cataract surgery improves visual outcomes, particularly in cases with advanced diffractive optics. In the United States, we do not have access to low power toric lenses, so we should be utilizing peripheral corneal relaxing incisions (PCRIs) for optimal visual outcomes.11-13
However, PCRIs are not a standard component of residency or fellowship education. I would argue that more than 95% of the current PCRIs performed are being created with the use of the femtosecond laser. (More on astigmatism treatment below.)
PERFECTING CAPSULOTOMY SIZE AND CENTRATION
Of course, every cataract surgeon can make a pretty reliable capsulorrhexis, but very rarely can they make it a perfect centered circle of a specific size that could potentially allow for perfect capsule/optic overlap. That’s important, because those traits may facilitate optic capture or advance IOL optic designs on the horizon. Many studies have shown that the femtosecond laser performs more precise, centered capsulotomies as compared with manual capsulotomies.14-16 With more advanced IOL designs such as diffractive optics, pinhole apertures and modular optics, lens centration and capsule/optic overlap are integral to achieving the best clinical outcome (see “Get ready for truly accommodating lens implants”).
In addition to this capsulorrhexis advantage, FLACS is also helpful in rapidly creating a complete capsulotomy in complex cases such as white cataracts, which have an increased propensity to radialize due to the pressure of lens material within the capsular bag.17 Cases with zonular compromise, such as traumatic cataracts and pseudoexfoliation cataracts, may also be facilitated with FLACS, due to the absence of tension on the zonules during a FLACS capsulotomy, which may occur if the capsule is pulled in a circumferential pattern with a manual instrument during the formation of a continuous curvilinear capsulorrhexis.
LESS TRAUMA, LESS ENERGY
One of our primary goals for cataract surgery is to keep the surgery as atraumatic as possible. We have many techniques and tools to help us achieve this goal, including advances in phaco machine technology that help us modulate energy and improve fluidics, advances in nuclear disassembly techniques (such as chopping instead of grooving) and techniques such as operating at the iris plane instead of near the corneal endothelium to reduce impact on the delicate endothelial cells. These advances are designed to hasten visual recovery, to provide an optimal visual outcome and to maintain the long-term health of the eye.
FLACS is yet another tool/technique that helps us move toward these goals of less traumatic surgery with faster visual recovery and less consequence to surrounding tissues (such as the corneal endothelium).17,18 Studies have shown that femtosecond lasers allow us to use less energy during cataract surgery.7-10 In very dense nuclear sclerotic cataracts, or in patients with shallow anterior chambers (short eyes or narrow angles) or Fuchs’ dystrophy (particularly when trying to spare the patient from an endothelial keratoplasty), I find FLACS very helpful, as these specific situations can lead to using more energy and thus result in damage to endothelial cells.
In fact, FLACS is so helpful in these cases that in many academic environments we choose to use the laser for these patients for free since this is not a billable service for this indication.
Several studies have shown preservation of endothelial cells with FLACS as compared to standard cataract surgery.17,18 In addition, Dick et al showed that, in some cases, visual recovery may occur more rapidly after FLACS as compared with traditional cataract surgery.13
The femtosecond laser is a particularly useful tool in challenging cases where we may want to limit manipulation of the lens or capsule to avoid zonular stress.5,10 Traumatic cataracts and pseudoexfoliation cataracts with weak zonules and unstable capsular bag complexes are perfect examples.
BETTER CONTROL OF ASTIGMATISM
Prior to the FDA approval of FLACS, very little attention was paid to correction of astigmatism, particularly to correction of lower amounts of astigmatism (under 1.25 D). This was the same year that Doug Koch, MD, delivered the Charles Kelman Innovator’s Lecture at the ASCRS meeting on the impact of posterior corneal astigmatism. This was also around the same time that the premium IOL channel started to increase.
FLACS popularity and premium IOL usage have grown together over the past decade but have always been limited by financial concerns and issues regarding surgeon confidence with certain premium IOL technologies. Additionally, given our lack of training with manual PCRIs, most surgeons rarely perform them. In my experience, more aggressive astigmatism control using FLACS-created PCRIs has helped improve visual outcomes with diffractive IOL technologies, which have been found to be more sensitive to small levels of residual astigmatism.
CONCLUSION
In my practice, the femtosecond laser is one of several tools I can use to help provide my patients the best experience during cataract surgery. When patients are educated about the compelling data behind FLACS, they find the concept of using a laser to facilitate the accuracy, correct astigmatism and reduce energy delivered during their surgery to be very appealing.
I plan to continue to use FLACS to facilitate my cataract surgeries, and I embrace any other advancements in phaco technology or techniques that will help me to provide the very best experience for my patients. OM
References
1. Day AC, Burr JM, Bennett K, et al. Health technology assessment: Femtosecond laser- assisted cataract surgery compared with phacoemulsification: the FACT non-inferiority RCT. Health Technol Assess. January 2021 25:1-68.
2. Abell FG, Darian-Smith E, Kan JB, Allen PL, Ewe SYP, Vote BJ. LRCS versus standard phacoemulsification cataract surgery: outcomes and safety in more than 4000 cases at a single center. JCRS 2015; 41:47-52.
3. Schweitzer C, Brezin A, Cochene B, et al. FEMCAT study group . Femtosecond laser-assisted versus phacoemulsification cataract surgery (FEMCAT): a multicenter participant-masked randomized superiority and cost-effectiveness trial. Lancet. January 2020. 395:212-224. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(19)32481-X/abstract. Accessed Mar. 1, 2024.
4. Nithianandan H, Jegatheeswaran V, Dalal V, Arshinoff SA. Refractive laser-assisted cataract surgery versus conventional manual surgery: Comparing efficacy and safety in 3144 eyes. Am J Ophthalmol. 2019, 2026:32-39.
5. Scott W, Tauber S, Gessler JA, Ohly JG, Owsiak RR, Eck CD. Comparison of vitreous loss rates between manual phacoemulsification and femtosecond laser-assisted cataract surgery. J Cataract Refract Surg. 2016;42:1003-1008.
6. Hou JH, Prickett AL, Cortina MS, Jain S, de la Cruz, J. Safety of femtosecond laser-assisted cataract surgery performed by surgeons in training. J of Refract Surg. 2015;31:69-70.
7. Abell RG, Kerr NM, Vote BJ. Toward zero effective phacoemulsification time using femtosecond laser pretreatment. Ophthalmology. 2013 May;120:942-948.
8. Conrad-Hengerer I, Hengerer FH, Schultz T, Dick HB. Effect of femtosecond laser fragmentation on effective phacoemulsification time in cataract surgery. J Refract Surg. 2012 Dec;28:879-83.
9. Daya SM, Nanavaty MA, Espinosa-Lagana MM. Translenticular hydrodissection, lens fragmentation, and influence on ultrasound power in femtosecond laser-assisted cataract surgery and refractive lens exchange. J Cataract Refract Surg. 2014 Jan;40:37-43. Epub 2013 Nov 22.
10. Assaf AH, Aly MG, Zaki RG, Shaaban YM, Aziz BF. Femtosecond laser-assisted cataract surgery in soft and hard nuclear cataracts: A comparison of effective phacoemulsification time. Clin Ophthalmol. 2021 Mar 10;15:1095-1100.
11. Rigi M, Al-Mohtaseb Z, Weikert MP. Astigmatism correction in cataract surgery: Toric intraocular lens placement versus peripheral corneal relaxing incisions. Int Ophthalmol Clin. 2016 Summer;56:39-47.
12. Lake JC, Vitor G, Clare G, Porfírio GJ, et al. Toric intraocular lens versus limbal relaxing incisions for corneal astigmatism after phacoemulsification. Cochrane Database Syst Rev. 2019 Dec 17;12:CD012801.
13. Conrad-Hengerer I, Al Sheikh M, Hengerer FH, Schlutz T, Dick B. 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 Jul;41:1356-1364.
14. Lawless M, Bali SJ, Hodge C, Roberts TV, Chan C, Sutton G. Outcomes of femtosecond laser cataract surgery with a diffractive multifocal intraocular lens. J Refract Surg 2012, Dec; 28: 859-864.
15. Filkorn T, Kovacs I, Takacs A, Horvath E, Knorz MC, Nagy ZZ. Comparison of IOL power calculation and refractive outcome after laser refractive cataract surgery with a femtosecond laser versus conventional phacoemulsification. J Refract Surg. 2012 Aug 28:540-544.
16. Conrad-Hengerer I, Hengerer FH, Joachim SC, Schultz T, Dick HB. Femtosecond laser-assisted cataract surgery in intumescent white cataracts. J Cataract Refract Surg. 2014 Jan;40:44-50. Epub 2013 Nov 20.
17. Schroeter A, Kropp M, Cvejic Z, Thumann G, Pajic B. Comparison of femtosecond laser-assisted and ultrasound-assisted cataract surgery with focus on endothelial analysis. Sensors. 2021;21: 996. https://www.mdpi.com/journal/sensors.
18. Al-Mohtaseb Z, Yesilirmak N, Waren D, Donaldson, KE. Comparison of corneal endothelial cell loss between two femtosecond laser platforms and standard phacoemulsification. J Refract Surg 2017, Oct 1; 33: 708-712. https://tinyurl.com/4wyfe3tb. Accessed Mar. 1, 2024.
