Femtosecond Laser Clear Corneal Incisions

This is certainly an exciting time in the development of laser applications for cataract surgery. Surgeons have a great deal to consider, though, in deciding which technologies might benefit our patients and our practices. So far, I remain somewhat skeptical about the potential return on investment from adding a second, cataract-only femtosecond laser to my practice.

However, I am interested in the clinical benefits of laser-assisted cataract surgery and the practice advantages of being able to market bladeless surgery. I think we may get the biggest “bang for the buck†in both areas from corneal applications of femtosecond technology, including clear corneal incisions and arcuate intrastromal incisions for the correction of astigmatism.

We already have extensive experience with corneal femtosecond lasers, with more than five million femtosecond LASIK procedures globally to date. Eliminating bladed incisions is the part of laser cataract surgery that I believe will be most appealing and easiest for patients to understand, while at the same time potentially reducing risk and improving outcomes.

And, of course, laser cataract surgery is a much more reasonable proposition financially for surgeon and patient if we can utilise the lasers we already have. For all these reasons, I have been investigating cataract surgery applications for my current femtosecond lasers (FS60 and iFS, Abbott Medical Optics).

Clear corneal incisions

We have now performed laser CCIs in 16 eyes, with three-month data available for 10 eyes. In the first few eyes, I made a straight, 30° entry angle into the anterior chamber. Although the wounds looked good and all these eyes achieved good results, two had Seidel wound leaks on day one, so we refined the technique to achieve better wound sealing.

My current approach relies on the IntraLase-enabled keratoplasty (IEK) software along with a mask to control the incision size at 2.3 or 2.6mm. This represents an off- label use of approved technology in the US. I create a three-step, multiplanar incision that is much stronger than my initial uniplanar incisions. There is very precise wound apposition and sealing, as can be seen on postoperative OCT images (Figures 1a-c).

At three months post-op, all eyes had BCVA of 20/20 or better. There was no trauma to Descemet’s and no problems in either group with wound leak or incision gaping while the femtosecond laser suction was on.

Similar to bladeless LASIK, femtosecond laser CCIs offer a theoretically lower risk of complications such as wound leaks and early or late ingress of tear fluid into the anterior chamber. It may even reduce the risk of endophthalmitis that has been associated with CCIs in the past.

Arcuate incisions

We have also treated three eyes with intrastromal arcuate incisions using the iFS laser. Initial post-op day one results were very good. The hope and expectation is that the astigmatic correction will endure over time. Immediately post-op, there is a very interesting separation of the incision by the opaque bubble layer on OCT. To me, this is a good indication that, while the cornea anterior and posterior to the incision is intact, there is a distinct separation of the corneal lamellae in the desired location.