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Device helps set standard in pupil dilation
The Malyugin Ring 2.0 was designed for smaller-incision cataract surgery.
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Performing cataract surgery in patients with small pupils can be daunting for even the most skilled and experienced surgeon. Inadequate pupil dilation can lead to a host of problems, including iris damage, bleeding and prolapse, anterior capsule damage and misalignment of the IOL; therefore, it is necessary to ensure that the pupil is adequately dilated before proceeding with surgery.
Pupil dilation
One of the problems associated with traditional pupil expanders is that they may extend surgery time and overstretch the iris sphincter. These were the issues that drove me to develop the Malyugin Ring (MicroSurgical Technology), a square-shaped device with four paper clip-like circular scrolls that provide eight points of fixation and ensures uniform dilation of the pupil and circumferential protection of the iris.
One of the key advantages of the Malyugin Ring is that it makes negligible stress to the iris tissue, thereby minimizing the risk of damage to the iris sphincter. Its ultrathin profile also means that it is less likely to reduce the space in the anterior chamber available for instrument manipulations. This in turns reduces the likelihood of viscoelastic becoming trapped underneath. In addition, its low profile helps prevent the ring from making contact with the corneal endothelium during insertion and removal. Because the device is inserted through the main incision, the surgeon does not need to create any extra incisions.
Surgical technique
The device is easy to implant. After creating the anterior capsulorrhexis, I inject a highly viscous ophthalmic viscosurgical device (Healon5, Abbott Medical Optics/Johnson & Johnson Vision) behind the iris in four points corresponding to the intended position of the scrolls on the iris margin. When injecting the leading scroll, I position the injector tip close to the iris margin in order to better control engagement of the scroll with the iris. The ring is then injected while the injector is slowly retracted back in the direction of the main incision. Two side scrolls usually catch the iris simultaneously at this time. The last scroll is disengaged from the injector hook and positioned in place with the help of the ring manipulator.
As far as I am aware, there was no great skepticism about the ring, although there are some technical nuances that surgeons have to learn in order to handle the device properly. The device was well accepted by surgeons from the beginning, and I believe this is because they found it easy to implant, intuitive and straightforward to use.
New developments
Despite the popularity of the original version of the Malyugin Ring, it is important to keep improving the experience of both doctors and patients. In recent years, cataract surgeons have realized the clinical advantages of using smaller incision sizes. Consequently, incision sizes smaller than 2.2 mm are becoming more commonplace due to improved phaco systems, new IOLs with improved delivery systems and also in part to femtosecond lasers, which allow surgeons to create an incision of a precise depth and length. To this end, we recently introduced the next-generation Malyugin Ring 2.0, which goes through a 2-mm incision. I believe it will be much easier for surgeons who perform small-incision surgery to use than the original ring.
Although introducing a pupil expander through a small incision sounds straightforward enough, it is in fact challenging. When MST and I were developing the Malyugin Ring 2.0, we experimented with many different materials and finally settled with 5-0 polypropylene, which is thinner and more flexible than the original 4-0 polypropylene material. This material is also gentler and will not damage the delicate tissue of the eye. The Malyugin Ring 2.0 includes a new injector and holder, and a smaller thread and scrolls.
I believe that surgeons who are still using 2.2-mm or larger incisions will also find the new version of the device useful for their patients because the smaller size injector minimizes stress to the corneal wound.
It was important to me that the Malyugin Ring 2.0 was as easy to insert and remove as the original device. Consequently, there is no need for any additional training or any learning curve associated with the next-generation ring. Surgeons simply use the Malyugin Ring 2.0 in the same way as the original ring. Moreover, like the original version, the Malyugin Ring 2.0 is available in diameters of 6.25 mm and 7 mm.
Surgeons can expect to see continuous developments because cataract surgery is continually evolving. In this way, I hope that the Malyugin Ring continues to set the standard in pupil dilation.
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- Boris Malyugin, MD, PhD, is a professor of ophthalmology and the deputy director general at the S. Fyodorov Eye Microsurgery State Institution. He can be reached at email: boris.malyugin@gmail.com.
Disclosure: Malyugin reports he receives royalties from MicroSurgical Technology.