As refractive lens exchange becomes increasingly popular, surgeons continue to seek better methods to improve safety and control, ensure a high level of success, and reduce complication rates. I have found that many surgeons are still cautious with specific elements of the lens exchange, including: (1) not rupturing the capsule, (2) finding good centration as to not affect the lens function, (3) correctly controlling and sizing the capsulorrhexis to ensure proper lens positioning, and (4) protecting the eye from endothelial cell loss.
We have used ophthalmic viscosurgical devices (OVDs) for the past 25 years, and I believe they are an extremely helpful, but underutilized, tool that addresses several of a surgeon's major concerns during refractive lens exchange.

CREATING A PREDESIGNED CAPSULORRHEXIS
Fill the anterior chamber with Healon 5. Our method creates a predesigned capsulorrhexis and a perfectly centered IOL using Healon 5 (Advanced Medical Optics, Inc., Santa Ana, California). To improve the procedure and predesign a capsulorrhexis with a normal lens, fill the anterior chamber to approximately 70% with Healon 5. Next, add small boli of OVD injections into the central part of the lens, just anterior to the central capsule (Figure 1). These injections will form dimples and ditch the central part of the lens, which is intraoperatively indicated by a ring reflex that will predetermine the exact size of your capsulorrhexis. No matter what way one pulls with the forceps—centrally, peripherally, up, or down—the capsulorrhexis is always going to follow the ring reflex created by the OVD injections (Figure 2).

In a mature partially liquefied lens, this method should be performed with the anterior chamber filled to 70% with OVD. The central anterior capsule should be stained with trypan blue ophthalmic solution (Vision Blue; Dutch Ophthalmic Research Center International, Zuidland, Netherlands). Microboli injections of Healon 5 will ditch and dimple the center of the mature lens (Figure 3). It should be noted that the capsulorrhexis may be predesigned and performed safely in a completely liquefied milky-white cataract (Figure 4). With this method, no liquefied lens matter will invade the chamber and obscure the view. Before the capsulorrhexis is performed, you may use a special forceps to measure the size of the ring reflex and center the refractive lens.

OVD for viscophaco. During viscophaco, phacoemulsification is performed at the level of the capsular bag only, while the rest of the anterior chamber remains under a cushion of the OVD. Optimally, you want to have some flow and turbulence, however, it should not be very high. This differs from the standard machine settings often used in the United States, where flow rates may increase up to 50 cc to 60 cc fluid movements. In viscophaco, the flow setting should be approximately 22 cc to 24 cc. This way, ruptured molecules only occur adjacent to the area where you are working, while the Healon 5 remains in the chamber as a cushion. Since less fluid is moving through the eye, the cornea is protected. Additionally, the workspace is 0.1 cc inside the deeper chamber instead of the typical 0.3 cc of the whole anterior chamber.

For viscophaco rotation, I use the phaco machine in a lower setting, maintaining tip occlusion as often as possible. Additionally, I use suction with very little phaco energy whenever a piece of the lens is inside the phaco tip. I suggest placing the tip on the side of the lens and turning it on slowly to obtain microocclusional breaks. This technique ensures that the eye experiences minimal turbulence and that the lens slowly moves and rotates into the phaco tip, rather than chasing the lens fragments with the phaco tip. This procedure works for a nucleus hardness of up to 2+. Use a traditional technique for harder nuclei. Even with a traditional chop technique, however, Healon 5 remains above the lens during the procedure.

Overall, I have found that viscophaco reduces fluid turbulence in the anterior chamber. With less fluid turbulence, the capsule is less likely to flutter. There is also less likelihood of engaging, rupturing, or breaking the capsule. I feel that this technique creates a safer environment for refractive lens exchange.

OVDs may be used throughout phacoemulsification to address many steps—from predesigning a capsulorrhexis to protecting the capsule against damage during phaco. These features answer some of the safety concerns that doctors may have throughout the various steps of refractive lens exchange procedures.

Manfred R. Tetz, MD, Professor of Ophthalmology, is Director of his private practice, Eye Center-Spreebogen, in Berlin, and Scientific Director of the Berlin Eye Research Institute. Professor Tetz states that he has no financial interest in the companies or products mentioned. He has, however, been a consultant to Advanced Medical Optics, Inc., and performed studies with various OVD manufacturers. Professor Tetz is a member of the CRST Europe Editorial Board. He may be reached at +49 30 398098 0; info@augentagesklinik-spreebogen.de.