In April, the FDA approved the first Collamer intraocular lens (Staar Surgical). Robert Kershner, MD, FACS, has been evaluating this IOL since 1993 and prefers it above all others. In an exclusive interview with EyeNet, he tells us why:
How does this lens differ from other IOLs on the market? The Collamer IOL is the first FDA-approved IOL made of a biocompatible, collagen-hydrogel copolymer, with a high water content, that closely approximates the living lens. (This is the same material used for the new Implantable Contact Lens, which is undergoing FDA trials.) The IOL is very thin, yet it is the most durable lens I have ever used. PMMA IOLs can scratch and crack and haptics can break, silicone IOLs can shear and tear, acrylic IOLs can fracture, but the Collamer IOL can be twisted, pulled and handled without tearing or breaking.
How is the biocompatibility of this lens better, especially for patients with diabetes, glaucoma, uveitis, and so forth? The IOL is compatible with eyes with preexisting pathology because of the nature of its cross-linked polymer, making it nonreactive to degradation and cellular infiltration. The high water content encourages its biocompatibility by making it mechanically buoyant and almost weightless in aqueous.
What is your background experience with this lens? I first saw the lens used, employed it in surgery, and followed postoperative patients implanted with the IOL, in 1993 in Moscow, Russia, with Dr. N. Svyatoslav Fyodorov. We brought the technology back to the United States where STAAR surgical acquired the rights to the material and design and commenced the FDA studies that culminated in the lens approval this year. I have personal experience with the implantation of the IOL in several dozen patients followed for up to three years.
What adverse effects or complications have you encountered with this lens? The lens is crystal clear in water and difficult to detect. It also sits very far back within the capsular bag once implanted into an aphakic eye. When first examined postoperatively, many surgeons mistakenly think the IOL has dislocated. Preoperative IOL calculations need to take into account that this IOL sits the most posterior of any IOL we have ever used. This may be an advantage in preventing capsular opacification postoperatively. In fact, this lens has one of the lowest YAG rates of all IOLs studied. Surgeons, however, must be careful in handling the IOL and loading it into the injector, because it may be difficult to detect if lost.
Is there anyone who should not receive this lens? If the capsular bag is compromised, precluding in-the-bag implantation of the IOL, it should not be implanted.
How is the lens implanted; are special instruments or techniques needed? Surgeons experienced in implanting IOLs through incision sizes of less than 2.0 mm will love this lens. Prior use of the Staar Microinjector makes use of this lens routine. The system creates a completely closed environment for IOL implantation. First, remove the lens from its vial (it is shipped and stored in balanced salt solution, much like a contact lens, due to its high water content), place it into the injector cartridge and position it into the injector (all disposable). Then gently insert the nose cone into the clear cornea incision and inject the lens entirely into the capsular bag in one controlled, smooth implantation. It need not be repositioned once implanted, and there is no up or down side to the IOL.
Closing comments? Surgeons are going to embrace the advantages of an IOL that allows rapid, simple implantation without the hassles of haptic manipulation or the concerns over silicone versus PMMA IOLs. This new generation of IOL technology will allow the general cataract surgeon to correct all forms of ametropia with the hyperopic, myopic, and toric IOL.
Dr. Kershner has no financial or proprietary interest in the IOL, instrumentation or in STAAR Surgical.
Robert M. Kershner, MD, FACS
Director, Eye Laser Center
Clinical Professor of Ophthalmology, University of Utah School of Medicine, Salt Lake City
Eye Laser Center
1925 West Orange Grove Road
Tucson, Arizona USA 85704-1152
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