I developed my admittedly strong preference for hydrophobic acrylic IOLs when I first worked with the AcrySof MA60BM (Alcon Laboratories, Inc., Fort Worth, TX). Currently, I favor the Sensar with OptiEdge (Advanced Medical Optics, Inc., Santa Ana, CA) for the majority of my cataract cases. This three-piece IOL combines the PCO-reducing feature of a posterior, squared optic edge with an advanced edge-modification technology that disperses unwanted images. I enjoy implanting this lens because, like other hydrophobic acrylics, it unfolds in a slow, controlled fashion within the eye. That trait allows me to place the lens precisely, even in eyes with damaged capsules.
IMPLANTATION WITH A FORCEPS
Until recently, I preferred to insert the Sensar with OptiEdge using a folding forceps. I found that this method reliably placed the IOL in the capsular bag and required little or no manipulation once the lens was inside the anterior chamber. More importantly, I could stabilize the eye at the sideport incision during the insertion and thereby maintain complete control, even in difficult, moving patients.
The only drawback to inserting the lens with a forceps was the IOL's tendency to adhere to itself. In a study of a variety of cohesive and dispersive viscoelastics, I demonstrated that coating the IOL with a cohesive viscoelastic 4 minutes before folding it considerably reduced self-adherence.1 Further experimentation showed that coating the Sensar lens for 4 minutes with CoEase (Advanced Medical Optics, Inc.) seemed nearly to eliminate self-adherence.
EARLIER INSERTION SYSTEMS
Despite my success with forceps insertion of the Sensar with OptiEdge, I recognized that using an insertion system would reduce the IOL's potential for contamination. Additionally, an insertion system could be preloaded by my OR staff and would allow me to use smaller incision sizes.
The early insertion systems for the Sensar with OptiEdge yielded consistent, although unspectacular, results. The loading of these systems was straightforward, and the incision size was typically 3.3 to 3.4 mm after insertion. During implantation, the IOL's progress through the cartridge seemed slow, however, and I had to rotate the inserter in order to maintain the optic's proper orientation. Although one-stage insertions were the norm, the system's plunger would occasionally trap the trailing haptic, a problem that forced me to dial in the IOL as a second stage of the insertion.
THE ADVANTAGES OF THE NEW SYSTEM
The Unfolder Emerald system (Advanced Medical Optics, Inc.) has proven to be a significant advancement in insertion technology for the Sensar with OptiEdge. The system's delivery mechanism features larger threads, so I do not have to twist the insertion device as much in order to deliver the IOL into the bag. The progress of the IOL is now more efficient as well. The larger threads reduce the amount of force needed to push the IOL through the cartridge, but delivering a full-sized, three-piece lens through a smaller cartridge necessitates greater compressive force. As a result, lubricating the IOL becomes important.
I informally evaluated the ability of a cohesive (CoEase) and a dispersive (Vitrax; Advanced Medical Optics, Inc.) viscoelastic for varying lengths of time on the IOL and inside the cartridge to enhance the performance of the Unfolder Emerald system. Vitrax seemed suited for “load-and-go” delivery and outperformed the other viscoelastic. CoEase functioned much better as a lubricant if applied to the interacting surfaces for approximately 4 minutes prior to folding and loading the IOL. Some force during plunger rotation is necessary, but the improved lubrication makes this task considerably easier.
The inserter's beveled tip passes through an unenlarged 2.8-mm phaco incision (Figures 1 and 2), and the postinsertion incision is consistently 3.0 mm. I use a limbus-based, Langerman-hinge incision and have not seen any appreciable induced astigmatism. Longer follow-up will be necessary to confirm this observation, but I believe that the narrower width of the phaco incision permits a slightly shorter tunnel that maintains the wound's astigmatic neutrality.
Most importantly, I no longer have to rotate the device to keep the IOL oriented. I simply stop advancing the plunger via the screw mechanism as the optic is delivered. Turning the barrel of the inserter perfectly positions the rod's tip for capsular bag placement of the IOL. The rod travels better, which makes it much more useful for one-stage implantations, and its sloped tip exits the eye smoothly with little chance of trapping the haptic.
CONCLUSION
When inserting the Sensar with OptiEdge using forceps, I have been impressed by the improved handling characteristics that the hydrophobic acrylic lens displays after a prolonged surface application of CoEase. I previously used cohesive viscoelastics for space-filling needs only. Knowing that CoEase will successfully prevent the IOL from adhering to itself and improve the lubrication of the Unfolder Emerald system makes me wonder what additional applications might exist for this class of agents.
I have used a forceps to implant hydrophobic acrylic lenses since 1995, but the Unfolder Emerald system has allowed me to trust the consistency of an inserter. The forceps provided me with precise intraocular control, but I am pleased by the simplicity of the Unfolder Emerald system's improved one-stage delivery. I no longer periodically project an IOL across the OR as I try to fold it. I do not have to worry whether the IOL was stored in a cold environment. Forceps marks are now in my past. Finally, although I did not consider astigmatism to be much of an issue with a phaco incision of 3.8 to 3.9 mm, I believe its impact will be further reduced with incisions of 3.0 mm.
Steven H. Dewey, MD, practices in Colorado Springs, Colorado, with the Colorado Springs Health Partners. He is a consultant for Advanced Medical Optics, Inc. Dr. Dewey may be reached at (719) 475-7700; sdewey@cshp.net.1. Dewey SH. Forceps insertion with incisional anesthesia for Sensar intraocular lenses. J Cataract Refract Surg. 2002;28:1097-1104.
