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Through the years of fixating IOLs in challenging cases
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In the 1980s as the director of the Cornea Service at the University of Minnesota, I was referred several hundred patients with closed-loop anterior chamber IOLs, usually so-called Leiske anterior chamber lenses originally manufactured by Surgidev, with significant complications. The typical patient would present with pseudophakic bullous keratopathy. Most of these eyes had undergone intracapsular cataract extraction, so there was no capsular support. Often there was associated peripheral anterior synechiae, cystoid macular edema and, in many cases, secondary glaucoma. The surgery to rehabilitate these eyes in those days involved penetrating keratoplasty combined with IOL exchange. After dissecting out the closed-loop IOL and performing subtotal anterior vitrectomy and in many cases a suture iridoplasty, I was uncomfortable placing another anterior chamber IOL.
Working with several fellows, including Steve Lane, MD, S. Gregory Smith, MD, Thomas Lindquist, MD, PhD, and Richard Duffey, MD, we developed an effective method using ab interno methods to scleral fixate a one-piece or three-piece posterior chamber IOL to the sclera under a scleral and conjunctival flap. With Alcon, we designed the all-PMMA CZ70BD posterior chamber IOL with a 7-mm optic, and with Storz, the P366B one-piece all-PMMA posterior chamber IOL with a 6.5-mm optic. These IOLs had a fixation hole in the haptic, which for me made the surgery easier. I started with 10-0 polypropylene suture and was very happy with my outcomes.
Unfortunately, I was surprised 10 to 15 years later when some of these patients presented with a broken suture. Biodegradation or perhaps chafing on the hole in the haptic were potential causes of the broken sutures. The ones where I could see the area of suture failure suggested the most likely cause was biodegradation. Most of the time I was able to fix these by suturing the subluxated haptic to the iris, and I learned to suture both sides to avoid a second subluxation a few years later if the other suture failed.
That prompted me to look for another alternative. I had used 11-0 polyester sutures (Mersilene) in many grafts, and even on the surface exposed to ultraviolet light, I had never seen even one interrupted or running polyester suture biodegrade. So, I switched to 10-0 Mersilene. With up to 25 years follow-up, I have yet to see one of these polyester sutures break or biodegrade. Others switched to 9-0 polypropylene or 8-0 Gore-Tex sutures. These two sutures have also proven to be much more robust.
Recently, Amar Agarwal has pioneered a sutureless approach in which the IOL haptic itself is exteriorized and fixed into a scleral tunnel under a scleral and conjunctival flap. The technique requires moderate skill but has generated good outcomes to date with a reasonable complication rate. Even more recently, Yamane has described a very ingenious approach to scleral fixate a posterior chamber IOL without a scleral flap. This approach requires passing a needle obliquely transscleral from the surface of the eye into the anterior chamber and then placing the haptic end into the internalized needle and pulling it out through a scleral track. The end of the haptic is then lightly cauterized and buried into the scleral track. This is to me an exciting alternative to the Agarwal approach. (Good videos of all these techniques are available online, including Healio.com/OSN.)
Suture fixation of a posterior chamber IOL to the sclera with 10-0 polypropylene is no longer recommended, but good long-term outcomes with suture scleral fixation can be achieved with 10-0 polyester, 9-0 polypropylene and 8-0 Gore-Tex sutures. Suturing the IOL to the iris with polyester or polypropylene sutures also has a good clinical track record. I prefer to limit polyester and polypropylene suture fixation of IOLs to elderly patients over the age of 65 years to reduce the potential for late suture failure. In younger patients, 8-0 Gore-Tex suture fixation and the Agarwal or Yamane approaches to direct scleral fixation of the IOL haptics offer some theoretical advantage. However, we must keep in mind that follow-up remains fairly short for each of these fairly new surgical techniques.
Finally, many published clinical trials and my own personal experience over more than 30 years suggest that the short-term and long-term outcomes with a four-point fixation “Kelman”-style anterior chamber IOL are very competitive with the results obtained with any method of scleral fixation. While a perfectly done scleral-fixated posterior chamber IOL is elegant and aesthetically pleasing to look at postoperatively, the surgical challenges and postoperative complication rate may be higher in many surgeons’ hands than a well-done properly sized one-piece anterior chamber IOL. As always, the surgery needs to be customized for each individual patient, and surgeons who face these complex cases may choose to refer these challenging patients to a surgeon who performs them frequently.