Issue: June 2011
June 01, 2011
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Femtosecond laser-assisted cataract surgery

At Issue posed the following question to a panel of experts: What potential advantages and disadvantages do you see with the addition of femtosecond laser to cataract surgery?

Issue: June 2011
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Lucio Buratto, MD
Lucio Buratto

New door opened in field of cataract surgery

Lucio Buratto, MD:

In some phases of cataract surgery, the use of the femtosecond laser provides greater degrees of safety and efficacy, but most importantly, the use of this machine will reduce surgical trauma.

The advantages associated with the use of this laser in some surgical phases are unquestionably the precision of the cut, its predictability, its repeatability and the greater possibilities it provides in the planning of the operation.

The precision of the laser replaces surgery with cutting instruments (needles, scalpels, knives) and optimizes the corneal incisions.

The femtosecond laser will be used for the primary corneal incisions, for the accessory incisions (paracentesis) and for the relaxing incisions necessary when astigmatism is present. The astigmatism can also be corrected with greater precision compared with the traditional surgical methods (limbal corneal incisions).

In cataract surgery, the incision of the anterior capsule is an extremely important step because it creates stability of the capsular sac for the duration of the operation; using this laser, a precise capsulorrhexis can be created with a desired diameter that is well-centered and has strong resistant edges. Comparison of the classical manual capsulotomy and its laser counterpart demonstrates that the latter is a more precise and repeatable technique.

With multifocal or toric lenses, a rhexis of precise diameter improves the centering of the lens and reduces the lens displacement phenomena, ultimately translating into qualitatively improved vision.

The femtosecond laser can soften and split the nucleus of the opaque crystalline lens (cataract) into four, six or eight fragments; it can also be used to perform concentric cuts or split the nucleus into small cubes.

The fact that this laser machine can be used to fragment the nucleus inside the sac and perform a pre-chop of the nuclei of hard cataracts is also a major advantage.

A lower amount of ultrasound is required to fragment the nucleus, and this results in less stress applied to the zonular regions; in softer nuclei, the use of the ultrasound can be greatly reduced or completely eliminated, and the cataractous masses can be removed simply by aspiration.

Limited use of the ultrasound probe in the classical fragmentation technique will reduce the amount of mechanical manipulation and will consequently decrease the risk of damage to the ocular structures – the corneal endothelium and posterior capsule, for example – and complications, including infections, during the operation.

One negative factor is that, compared with the cost of handheld instruments or a phacoemulsifier, the femtosecond laser is a much more expensive piece of surgical equipment.

  • Lucio Buratto, MD, can be reached at Centro Ambrosiano di Microchirurgia Oculare, Piazza Repubblica 21, 20124 Milano, Italy; +39-02-6361191; fax: +39-02-6598875; email: office@buratto.com.
  • Disclosure: No products or companies are mentioned that would require financial disclosure.

Offers ideal rhexis creation

Massimo Camellin, MD:

Massimo Camellin, MD
Massimo Camellin

It is difficult to hypothesize the advantages and disadvantages of new technologies, as we have seen in the past that apparently safe techniques have shown important drawbacks (eg, hyperopic shift after RK).

Cataract surgery has become a popular and standardized procedure, and despite some small changes, I think it can be considered the same all over the world.

The advantage of a femtosecond laser could be, in my opinion, in the rhexis creation. The rhexis still has some poor precision aspects. We cannot be sure about the real diameter, as we observe it through the cornea and it widens the apparent diameter, and sometimes it is possible to have some escape lines toward the periphery.

New premium lenses need precise position in the bag, and only a perfect rhexis can lead to this result.

As for the need to fragment the nucleus, I do not think it is as useful because the new machines are effective and ultrasounds are not dangerous anymore for the cornea.

Do not forget that time is an important variable; it is possible that femtosecond cataract surgery will need more time for rhexis and nucleus fragmentation.

In short, I think femtosecond laser will be a useful instrument for ophthalmologists, and I am sure we will invent other applications with time.

  • Massimo Camellin, MD, can be reached at Via Dunant 10, 45100 Rovigo, Italy; +39-042-541-1357; email: cammas@tin.it.
  • Disclosure: No products or companies are mentioned that would require financial disclosure.

Promising technology, some potential drawbacks

H. Burkhard Dick, MD:

H. Burkhard Dick, MD
H. Burkhard Dick

Although we have no real hard evidence because prospective randomized trials have not been conducted yet, the options are great. Problems that we may be confronted with are how this fits into our daily lives in cataract surgery, for example, in patient flow, especially if this is a high-access and high-performer department. Another thing is payment. There is a big investment, of course, and currently it will only be for the cost of the paracentesis and the main incision, as well as the rhexis and the lens softening.

Another issue concerns astigmatic keratotomy. Currently there are no nomograms provided by the companies. I think that every company with a specific laser platform will have to perform their own studies in evaluating the exact parameters to use to treat the individual astigmatism. It is totally different from what was made mechanically with hands. We have the great option to perform astigmatic keratotomies that are nonperforating. That means they will not dissect through the Bowman’s membrane; therefore, we will not be confronted with gape and gape issues such as inflammation. But on the other side, if we do nonperforating astigmatic keratotomy with the femtosecond laser at the same time as the cataract surgery, we know it is not as efficient as full penetrating astigmatic keratotomy. We can expect treatment of, let’s say, up to 1.5 D of what is expected. But we do not know the effect, for example, if we now have the possibility to cut not vertically but with angulation. So there is a lot of leeway and a lot of things that have to be investigated.

What is really charming is not only what the laser options are now, but also the future options, concerning, for example, new treatment modalities in one session that have not been able to be conducted at the same time before. I am talking about maybe a combination of lens surgery with a pocket incision and implanting an intracorneal device. Another option will be, besides the astigmatic incisions, doing a lenticular anti-presbyopic treatment in a sighted eye without cataract that is presbyopic treatment on a lenticular base. There is a lot of work that can be scientifically conducted in the future and options that may arrive that we have not heard about. For example, a femtosecond laser adjustment of the lens intraoperatively — not a light adjustment, just a femtosecond laser adjustment — that has been shown by Josef Bille recently. The technology is there that you can adjust the lens power after the lens is implanted using the femtosecond laser.

You have a high investment, you have a lot of additional talk to see how you will get back the money, and you have to place this laser, which is big, in your OR, and not everyone has a big OR. This is still an intraocular procedure, so you have to do it under sterile conditions, and treatment needs to be performed by a medical doctor, not an optometrist, so a lot of questions are confronting us. There is no answer for everything, but I think this is really the next step, coming from intracapsular cataract surgery to extracapsular cataract surgery to phaco and now to femto-phaco. We will not totally go away from phaco, so it will be a femto-phaco combination. If you look at the future, it is all about progress. And what does progress mean? Progress means innovation, it means miniaturization, it means more automization, and it will be the convergence of technologies, which is phaco with femto. I think the key elements of progress will show that this technology will perfectly fit.

  • H. Burkhard Dick, MD, can be reached at University Eye Clinic, University of Bochum, In der Schornau 23-25, 44892 Bochum, Germany; +49-234-299-3101; email: burkhard.dick@kk-bochum.de.
  • Disclosure: No products or companies are mentioned that would require financial disclosure.

Many theoretical advantages, but studies needed

Jose L. Güell, MD:

Jose L. Güell, MD
Jose L. Güell

Theoretically, the advantages of using the femtosecond laser for some of the steps of cataract surgery would be to completely standardize the incisions and rhexis. This might be an advantage for IOL positioning and, for the same reason, with IOL functioning because some of the IOLs, especially the new IOLs, are dependent on positioning. So this might represent an advantage, but only mid-term studies comparing in a prospective manner the use of the femtosecond laser for the incisions and rhexis will demonstrate a superiority or not.

The second issue is regarding the use of the femtosecond laser to soften the cataract. Again, this is a much more theoretical advantage and disadvantage. The femtosecond laser will definitely help us to diminish the amount of ultrasound energy at the time of removing a cataract. It will allow different strategies, such as phaco rolling, which is the one that I am more focused on in dealing with medium to hard cataracts. If I have this femtosecond laser equipment, the phaco-rolling technique in hard cataracts will be much easier. Theoretically, it will improve our efficacy and thus safety in removing hard cataracts. But again, we will need two parts of equipment: first, with a femtosecond laser, and second, the removal with the phaco machine. Perhaps new complications or new limitations will appear that are unknown right now. So again, only prospective comparative studies will demonstrate if the use of the femtosecond laser at the time of softening the cataract will improve the final outcome.

I am very much in favor of this technology. Because of my explanation, it might seem I am against it, but I am not at all. I am in favor of using it because I really think these theoretical advantages will be demonstrated in the future, and most important, it will increase the global safety of cataract surgery. The only thing is that the advantages and some of the disadvantages of femtosecond technology today have not yet been demonstrated in properly designed multicenter studies.

  • Jose L. Güell, MD, can be reached at Munner 10, Barcelona 08022, Spain; +34-93-253-1500; email: guell@imo.es.
  • Disclosure: No products or companies are mentioned that would require financial disclosure.