It was 7 years ago, in 2009, that the first femtosecond laser received FDA approval for anterior capsulotomy creation during cataract surgery. Femtosecond lasers were already in widespread use for corneal refractive surgery since their 2002 FDA approval. Applying the laser energy further inside the eye seemed like a natural progression. We now have the ability to do many steps of cataract surgery with the femtosecond lasers: incision creation, corneal astigmatic treatments, anterior capsulotomy, nucleus division, cataract softening, and more. But does it make a difference? Is there an appreciable benefit to patients to elect (and pay) for the femtosecond laser treatment? It’s not such an easy question to answer because the best answer is, “It depends.”
THE FIRST VARIABLE: THE STEP OF SURGERY
Using a femtosecond laser to create corneal incisions is a reasonable option, but with the current programming, these incisions tend to be less likely to seal than those made with a keratome. The gold standard is still the use of a gem-quality diamond keratome in the hands of an expert surgeon. This produces incisions that are clean, precise, and well-sealing.
For the capsular opening, the femtosecond laser can create a perfectly round capsolotomy but many studies have failed to show a refractive benefit compared with a manually created capsulorhexis. With overlap of the optic edge for 360°, I see no difference in refractive outcome. Studies have shown that the femtosecond laser–created capsulotomy may not be as strong as the manually made capsulorhexis, but for most cases that should not make a significant difference.
For astigmatic corneal incisions, there may be a benefit in terms of refractive precision because the laser and its imaging allows for tailoring of the depth of the relaxing incision to the patient’ tissues when compared with manually created incisions. This, however, is limited because a toric intraocular lens is a far more accurate and predictable way of addressing 1 diopter or more of corneal astigmatism.
For nucleus division, studies have shown that using the femtosecond laser to divide or soften the cataract nucleus before phaco can reduce the total ultrasonic energy that is placed in the eye. The benefit is less corneal endothelial cell loss and quicker recovery. We have made large strides in the reduction of ultrasonic power use by incorporating phaco power modulations such as burst and pulse modes and by mechanical disassembly of the lens nucleus. Phaco chop results in less energy use than the divide-and-conquer method. If the surgeon is already using phaco power modulations and a chop technique, then the benefit of using a femtosecond laser to divide the nucleus is minimal.
THE SECOND VARIABLE: THE SURGEON
I attend hundreds of resident cataract cases per year, and a femtosecond laser would decrease the complication rate for my beginning resident surgeons. But this is a delicate balance, because while I want my resident surgeons to have the experience of trying new technologies like the femtosecond laser, I do not want it to come at the expense of developing manual skill and dexterity. Studies have also shown that there is a learning curve to incorporating the femtosecond laser in cataract surgery and that complications are more likely to occur in the initial period.
For a less experienced or less comfortable surgeon, the femtosecond laser can be a huge help because it can make the anterior capsulotomy and divide the nucleus consistently in nearly every case. There is no need to master the manual capsulorrhexis or learn phaco chop techniques. But what happens when the patient presents with a small pupil or an opaque cataract that prevents the laser energy from penetrating the lens?
For a more experienced surgeon, the additional steps of the femtosecond laser may just make the surgery slower and less efficient. Expert surgeons can already make a consistently good manual capsulorrhexis and divide the nucleus in a very efficient manner. For these skilled surgeons, the potential benefits of “femto phaco” are more limited, and the cost and efficiency issues may not make it as worthwhile.
I have found utility in using the femtosecond laser for unusual cases such as intumescent white cataracts, to avoid the Argentinian flag sign, and eyes with zonular laxity, in which a manual capsulorrhexis is challenging due to lack of capsular tension. Should my patients desire laser-assisted cataract surgery or if I can see a clear benefit to using it, I am happy to perform it. Perhaps the future, novel IOL designs may require a femtosecond laser to create an intricate capsular opening and then I’d certainly use it.
But for now, in routine cataract cases, the benefits of femto phaco are less pronounced in my hands. Ask other surgeons and you’ll likely get a range of answers across the spectrum. Like I said, it depends.