FEMTO FACTOR

Let it go

Advancing surgical techniques in laser-assisted cataract surgery requires embracing change.

By Scott LaBorwit, MD

Making progress with laser-assisted cataract surgery (LACS) requires a conscious decision to leave some traditional techniques behind, a choice that, for some surgeons, can be a major challenge. Over time, it’s natural to fall into a surgical comfort zone. However, surgeons interested in advancing their techniques and improving patient outcomes with LACS must be willing to push beyond these boundaries.

Evolution happens

Some surgeons are too change-resistant to ever make this leap. I know one who is still doing extracapsular cataract extraction, and is happy to tell you why this procedure, in his hands, is every bit as good as the newer phacoemulsification. I’m not sure this surgeon is aware that this “new” procedure he’s talking about has been around for more than 18 years. Although I disagree with his point of view, I just nod, knowing this doctor is too set in his ways to be convinced otherwise.

But what if every surgeon shared his opinion? It would be impossible for surgery to evolve. Major advances like phaco, folding implants and the femtosecond laser occur in small steps and can only be refined through their application and integration with other techniques. And often, advances in one area are the catalyst for progress in another. For example, phaco paved the way for small incisions; however, until folding implants became available, incisions had to remain large.

Ch-ch-changes

The LACS journey begins by adapting your procedure to integrate use of the femtosecond laser. My own technique has changed significantly over the three years I have been using LACS, and I expect it will continue to evolve.

For one thing, my corneal incisions are now very different. Initially, just being able to operate without blades was exciting; over time I evolved from a biplanar to a triplanar incision. In traditional cases my incision usually began near the limbus and often entered the anterior chamber proximal or distal to my intended cut. Now, my primary incision has an initial cut at 90 degrees to 40% of the cornea with a tunnel of 1,600 microns. In each case this incision is on the same axis and starts along the limbus. This change has allowed me to reduce my patient’s postoperative restrictions — such as no bending, lifting or activities like golf or tennis — from seven days to only two.

My nuclear removal using LACS no longer resembles my pre-laser procedure. In traditional cases, I sculpt a groove as narrow as possible to crack the lens. In LACS the lens is bowled out to 4.7 mm, since the laser cut is four cylinders in the nucleus to a depth that is within 500 microns of the posterior capsule based on the OCT imaging. The chop pattern cut is 5.3 mm, despite a 5.0 rhexus, to allow the lens to crack into four quadrants. The benefit of this technique is typically a 70% reduction of cumulative dispersed energy, and subjectively the lens removal is more predictable — all of which can have a positive impact on corneal edema and patient satisfaction with post-op day one vision.

Shake it off

In the recent past, using a diamond blade to cut 600-micron deep limbal relaxing incisions was impressive and exciting. I never thought I would see this knife sit on a shelf collecting dust (in a peel pack, of course). But with LACS, astigmatism is managed with astigmatic keratotomy (AK), using imaging that includes OCT measurements. This allows a precise location of the AKs at the 9-mm optical zone, 85% cornea depth and a precise chord length. I struggled in the past with the chord length precision since my markings were two purple dots often almost 1- mm wide each.

The precision level for managing astigmatism continues to evolve. New, in-clinic equipment allows me to measure the patient’s eye, via an image, while the patient is sitting down. This equipment takes the information and records the center of the undilated pupil and marks the limbal axis with photos of the limbal blood vessels. During the laser treatment, the imaging will line the eye up using the patient’s specific limbal vessels to account for torsion while the patient is in the supine position. Additionally, knowing the position of the undilated pupil, measured prior to surgery, allows the surgeon to strategically position the capsulorhexus at the time of surgery and aid in centration of the IOL.

For me, a substantial hurdle was letting go of traditional longitudinal phaco and creating a new phaco setting for patients who were undergoing LACS. I had learned cataract surgery on traditional phaco and was comfortable with this tried-and-true technology. But I soon learned that with the laser cutting the nucleus I could increase my vacuum setting, change my phaco energy type and cut the power by 50%. Currently in LACS patients, only torsional phaco is used with linear control.

Dream on

Change moves us out of our comfort zone, when it often seems easier to keep the status quo. But surgeons willing to embrace innovation can trust that their instincts will guide them forward successfully — and this, in turn, will contribute to the evolution of cataract surgery. Leaving pieces of your surgery behind brings the future of LACS even closer today. OM

Scott LaBorwit, MD, is a principal at Select Eye Care, with locations in Towson and Elkridge, Md., and is an assistant professor, part-time faculty, at Wilmer Eye Clinic of Johns Hopkins Hospital, Baltimore. His email is Sel104@me.com. Disclosures: Dr. LaBorwit is a consultant to and speaker for Alcon.