Early this year, Volk Optical (Mentor, OH) introduced the G-6 Gonio Lens—the first six-mirrored goniolens (Figure 1). With these mirrors equally aligned at 63°, the goniolens is designed to provide a complete 360° view of the anterior segment during glaucoma screenings with minimal manipulation of the lens. The G-6's mirrors are placed more closely together than a traditional four-mirror lens, which reportedly reduces examination times by allowing fast scanning and nearly eliminating the need to maneuver the lens. It has a tall, tapered profile and is designed to be used without any viscous interface solutions.
In an interview with Glaucoma Today, Jonathan Eisengart, MD, shared his experience with the G-6.
“The major benefit I've noticed when using a six-mirror lens, as compared to a four-mirror lens, is that I can visualize the vast majority of the angle without rotating the lens,” Dr. Eisengart said. “Using a four-mirror lens leaves blank areas that are not visualized between the mirrors. The sixmirror lens eliminates those blank areas. Although this is the most obvious advantage, there are also other benefits to using the G-6.”
Dr. Eisengart continued, “There is less distance to move from one mirror to the next, and although that does not sound important, it does make performing gonioscopy significantly quicker. I perform gonioscopy at least 10 times a day. If this lens saves me 30 or 60 seconds from each examination, that time adds up by the end of the day. Its smaller contact area also allows the G-6 to sit easily between the eyelids, especially if the patient is squeezing. It increases patients' comfort and is easier to get on the eye.”
For clinicians interested in trying the new goniolens, Dr. Eisengart had some advice. “One pearl I recommend for using the G-6 is to hold the lens in the same orientation every time,” he said. “I advise holding it so that you have a horizontal mirror at the 12-o'clock and 6-o'clock positions. That way, you can use a superior mirror to look at the inferior angle easily. For gonioscopy, you really want to start in the inferior angle because the structures are usually most obvious inferiorly. Also, because of the smaller contact area and longer length of the lens, it can be a little less stable on the eye and more likely to move on the eye's surface. You want to be careful not to apply any pressure and inadvertently indent the cornea, which can make the angles look open when they are not.”
He found the transition to the six-mirrored goniolens easy but said that clinicians who use a one-mirror goniolens will face a learning curve. “However, if you are already comfortable using a standard four-mirror goniolens that does not use a contact gel, there is just about no learning curve,” he noted. “You should be able to comfortably move to the six-mirror goniolens after performing three to five examinations.”
For more information about the G-6 Gonio Lens, visit http://www.volk.com.
Jonathan Eisengart, MD, is a staff glaucoma specialist at the Cleveland Clinic Cole Eye Institute. He acknowledged no financial interest in the product or company mentioned herein. Dr. Eisengart may be reached at (216) 445-9429; eisengj@ccf.org.
