Why Using a New-Generation Nd:YAG Laser Matters With Premium IOLs
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Why Using a New-Generation Nd:YAG Laser Matters With Premium IOLs
Using less energy is important.
By Richard L. Lindstrom, MD
Most of us likely view the Nd:YAG laser as a utility player in our ophthalmology practices. It is there when we need it, but it is not a piece of equipment that gets the spotlight. In general, the Nd:YAG laser enables us to safely and accurately create a capsulotomy or iridotomy using relatively low energy.
I have come to view Nd:YAG lasers in a different light, as my colleagues and I have incorporated more advanced technology IOLs into our practice. Here are some key reasons why you should consider updating your Nd:YAG laser if you are implanting premium IOLs.
ACCURATE AND EFFECTIVE
At Minnesota Eye Consultants in Bloomington, my colleagues and I have found that the newer-generation Nd:YAG lasers, such as the Ultra Q Nd:YAG Laser (Ellex, Adelaide, Australia), more accurately aim and control the delivery of energy than older platforms. The red diode aiming beam on the Ultra Q ensures that we hit our target. Using less energy is particularly important in eyes with premium IOLs, because we do not want to mark the optic. Other manufacturers (Table 1) have also emphasized the accuracy with which energy is delivered. For example, the Visulas YAG III (Carl Zeiss Meditec, Inc., Dublin, CA) has a four-point focusing beam system, and the Q-switched Opto Global Advant YAG laser (Opto, Adelaide, Australia) offers a dual-spot aiming system.
ND:YAG LASERS AND PREMIUM IOLS
With any of the premium IOLs available in the United States, including the Crystalens HD (Bausch + Lomb, Rochester, NY), the Acrysof Restor (Alcon Laboratories, Fort Worth, TX), and the ReZoom and Tecnis IOLs (both from Abbott Medical Optics Inc., Santa Ana, CA), you must customize the capsulotomy for the most effective results.
With the Crystalens HD, for example, the opening must be within the edge of the optic, and the IOL’s performance can be affected if the capsulorhexis is too small. A new-generation Nd:YAG laser can help to accurately and precisely enlarge the capsulorhexis and eliminate the need to return to the OR for capsular contraction syndrome with a refractive error shift. In some cases, extending the capsulotomy under the hinge and haptic can reduce consecutive myopia and/or astigmatism. Occasionally, I will also perform anterior capsular relaxing incisions in areas of phimosis to treat a hyperpopic shift. For best optical performance, multifocal IOLs need larger-than-standard capsulotomies that still stay inside the optic’s edge.
The accurate focus and more efficient energy levels of the Ultra Q allow my colleagues and me to create effective iridotomies before the implantation of phakic IOLs. The laser is useful for lysing capsular or vitreous strands, treating some vitreous opacities, and dusting the lens’ surface free of visually significant lenticular precipitates or pigment.
We have several different Nd:YAG lasers at our practice’s multiple locations. The newest, the Ultra Q, is my
favorite (see Tips for Effective Nd:YAG Capsulotomies in Eyes With the Crystalens). This laser can alleviate the need for more invasive surgical intervention in most cases, making treating unforeseen events less cumbersome for the patient and for me. ■
| TIPS FOR EFFECTIVE ND:YAG CAPSULOTOMIES IN EYES WITH THE CRYSTALENS |
|
The goal of selective Nd:YAG laser capsulotomy to treat capsular opacification with the Crystalens (Bausch + Lomb, Rochester, NY) and capsular contraction syndrome is to restore the capsular bag’s equatorial diameter. When the overall diameter of the Crystalens is decreased by capsular contraction, the IOL shifts either anteriorly or posteriorly with no capability for further movement, this reducing its effectiveness. Selective Nd:YAG laser capsulotomy settings. Each laser has a different threshold in terms of the formation of plasma and how much of the capsule it will disrupt. I recommend titrating the laser energy to create a posterior capsular opening of approximately 0.25 mm per laser shot. With the Ellex Ultra Q laser (Ellex, Adelaide, Australia), for example, I use about 1.9 mJ of energy. For a central posterior capsulotomy, I start the treatment at the center of the optic such that it radiates outward. I simultaneously control the diameter of the capsulotomy so that it does not extend beyond the edge of the optic. The endpoint is a round, central posterior capsulotomy that is approximately 3 mm in size. Round capsulotomies will not extend as much as a cruciate capsulotomy, and the former are more easily controlled and titrated. |
| TABLE 1. CURRENTLY AVAILABLE ND:YAG LASERS | |||||
| Manufacturer | System | Wavelength/Mode | Maximum Laser Energy | Features | Website |
|
Carl Zeiss |
Visulas |
Super |
Single pulse: 10 mJ, |
Pulse repetition rate: maximum 2.5 Hz |
|
| Ellex | Ultra Q |
10Q-switched, |
Continuously |
Pulse duration: 4 ns |
|
| Lumenis | Aura PT |
Fundamental |
Continuously |
Spot size: 8 μm |
|
| Nidek Inc. | YC-1800 |
Fundamental |
Continuously |
Spot size: 8 μm |
|
| Opto Global | Advant YAG Laser System |
Q-switched, |
N/A |
Firing rate of 2.5 Hz |
|
Richard L. Lindstrom, MD, is the founder of and an attending surgeon at Minnesota Eye Consultants, PA, in Bloomington. He is a paid consultant to Abbott Medical Optics Inc.; Alcon Laboratories, Inc.; and Bausch + Lomb. Dr. Lindstrom may be reached at (612) 813-3600; rllindstrom@mneye.com.