Are there benefits in performing cataract surgery with a femtosecond laser?
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Click here to read the Cover Story, "Technology upgrades strengthen foothold of femto in ocular surgery."
Automation provides enhanced safety, precision
Cataract surgery is a skill that is acquired over many years to become an expert, and even in the best of hands, there are countless potential errors that can happen.
The femtosecond laser is a machine that automates portions of the procedure to eliminate human error and ensure the good outcomes patients expect from modern refractive cataract surgery.
Capsulotomy is one of the most challenging parts of cataract surgery and requires patient cooperation because it is performed under topical anesthesia. If the patient moves during that part of the procedure, there can be tears in the capsule. In addition, the outcomes of advanced-technology IOLs are dependent on the lens being properly centered and stable with the edges of the capsulotomy overlapping the optic to prevent anterior prolapse or tilt. An automated procedure minimizes complications and maximizes centration and stability more than a human hand could ever do.
The second important feature is the fragmentation of the nucleus. When you apply laser energy to the nucleus, it softens up and can be more easily mobilized and rotated by the surgeon. This provides a lot less stress on the zonules. In addition, the fragmentation allows you to do less sculpting and to use less ultrasound energy in the eye. This results in a lower risk of breaking the capsular bag and significantly reduced endothelial cell loss, also in case of dense cataracts. You can eventually save eyes from needing a corneal surgery down the road, especially patients with Fuchs’ dystrophy who tend to develop persistent corneal edema after conventional phaco surgery.
There are other benefits when it comes to astigmatism management. We can use toric IOLs for larger amounts of cylinder, but the bulk of the population has less than 1 D. With iris registration and preprogrammed surgeon-defined nomograms, the laser has stepped up our ability to do precise low astigmatism treatments. Even for toric IOL cases, with iris registration and capsule marking technology, the femtosecond laser provides guidance on where to place the lens, improving the refractive outcomes for our patients.
Robert J. Weinstock, MD, is an OSN Technology Board Member.
There are limited advantages in expert hands
I am always a fan of having more tools in the toolbox, but despite more than a decade of use and hundreds of published papers about the topic, there is still controversy as to what are the potential advantages and disadvantages of using the femtosecond laser in cataract surgery.
I want to mention a recent paper by Stanojcic and co-authors, a single-center, randomized, case-controlled trial comparing femtosecond laser cataract surgery vs. conventional surgery at 12 months in 234 patients. It was a well-performed independent study conducted in the U.K. by experienced surgeons, and, importantly, patients did not have to pay for surgery, so there was no bias one way or the other.
No difference was found between the two methods in vision, refraction, adverse events or patient-reported outcomes via questionnaires. The only part of the surgery in which the femtosecond laser showed slightly better results was the treatment of astigmatism by intrastromal femtosecond laser-assisted astigmatic keratotomies as compared with manual limbal relaxing incisions. However, the mean astigmatism was 1.4 D, and we know that astigmatism above 1 D is better served with a toric lens anyway.
It seems like there are few, if any, clinical advantages of femtosecond laser-assisted cataract surgery in expert hands. If you are an experienced surgeon, for the vast majority of your cases, there is no frank need for a femtosecond laser. It is challenging to justify using it in its current form in a clinical setting unless further evidence arises to support its usage. However, for those surgeons who find it challenging to create a capsulorrhexis or difficult to chop the nucleus, perhaps the laser can help produce more consistent results in their hands.
I encourage you to learn to use the laser and any other potential tool that may assist in surgery. It is nice to have access to one, but for most patients, in expert hands, there is little upside. If I were to have cataract surgery tomorrow, I would not require a femtosecond laser — I would just want a highly experienced and talented surgeon. The hands are much more important than the machine.
- Reference:
- Stanojcic N, et al. Br J Ophthalmol. 2021;doi:10.1136/bjophthalmol-2020-316311.
Uday Devgan, MD, is Healio/OSN Section Editor.
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