Much excitement has surrounded the arrival of femtosecond lasers for cataract surgery. There is increasing curiosity about whether these lasers will live up to the hype. I have had the good fortune to be one of the first surgeons to use this technology. I know from my experience with the LenSx laser system (Aliso Viejo, California) that the use of femtosecond lasers for cataract surgery is promising. In this article, I focus on one of the key advantages of the system, integrated real-time optical coherence tomography (OCT) imaging. This component guides the surgical procedure and increases the safety and effectiveness of cataract surgery.
Cataract surgery with the femtosecond laser is unique, because the laser starts inside and then works its way to the surface. Therefore, the corneal incisions are the final step.
To begin the procedure, a curved patient-interface device is placed on the eye, and the laser is lowered into the docking position. LenSx's proprietary OCT imaging then captures the entire anterior segment with one scan and projects detailed images of all ocular structures onto the video microscope screen in 3-D and in their true orientation. Once the software calculates the laser treatment from preentered surgical parameters and patient data, the images of the proposed lens treatment pattern, anterior capsulotomy, and all corneal incisions are overlayed. The surgeon uses the touch keypad to modify centration and the placement of all incisions and confirm the proposed laser treatment as imaged on the screen; he initiates the procedure with a press of the footpedal. The procedure is displayed on the video screen and is completed in less than 1 minute (Figure 1).
In a study of laser capsulotomies that we performed at Semmelweis University in Budapest, Hungary, we compared capsulotomies created with the LenSx system to capsulorrhexes created manually. The LenSx group (37 eyes) had significantly better centration (P=.041) at 1 week and 1 month postoperatively. Additionally, the IOL overlapped with the capsular opening better in the LenSx group than in the manual group. This improved accuracy may reduce the risk of IOL decentration as the capsule contracts over time. The conclusion of our study was that real-time OCT imaging enhanced the safety of anterior capsulotomy creation.
Roger Steinert, MD, of the University of California, Irvine, studied the benefits of OCT imaging in other steps of femtosecond- assisted cataract surgery and found that clear corneal incisions created with the LenSx system (n=42) required no stromal hydration or sutures (Figure 2). Therefore, image-guided femtosecond laser corneal incisions were not only feasible with the LenSx laser system but also reproducible, with precise geometry and architecture. Most important, the incisions created with the LenSx laser were self-sealing, and there were no postoperative cases of endophthalmitis.
ONE LASER SYSTEM
We perform the laser procedure in a clean room and move the patient into the operating room to open the incisions with a blunt spatula. Because the eye remains a closed system until the incisions are opened, one laser can be used to prepare several patients for different operating rooms.
I have been working with the LenSx laser system for 2 years now, performing more than 300 laser refractive cataract procedures without complication. The procedure is efficient and accurate, and it increases safety for cataract procedures due largely to the use of real-time image guidance. The laser's integrated OCT system provides optimal planning of the cataract procedure based on 3-D images of all ocular structures in the anterior segment. The surgeon is able to deliver far more reproducibility with the precision of an all-laser cataract procedure, which should result in continually improved outcomes. I truly believe that laser refractive cataract surgery will make every procedure safer and will drive rapid innovation of technology and technique for the benefit of our patients.
Zoltan Nagy, MD, is a Clinical Professor in the Department of Ophthalmology at Semmelweis University, Budapest, Hungary. Dr. Nagy states that he is a consultant to LenSx Lasers, Inc. He may be reached at e-mail: firstname.lastname@example.org.