Anterior chamber vs. posterior chamber IOLs: What works best in eyes with no capsular support?
Matthew B. Goren, MD, FACS, and Mark Gorovoy, MD, discuss the merits of each approach.
Welcome to another edition of CEDARS/ASPENS Debates. CEDARS/ASPENS is a joint society of cornea, cataract and refractive surgery specialists, here to discuss some of the latest hot topics in ophthalmology.
In recent years, several new techniques have emerged for placing IOLs into the posterior chamber when there is insufficient capsular support. Most have involved scleral fixation. While these techniques are quite elegant and produce excellent outcomes, they may not always be feasible. Another option still commonly used is the placement of an anterior chamber IOL. There is much debate over which technique is best and if the use of an anterior chamber IOL is still considered a first-line treatment for eyes with no capsular support. This month, CEDARS/ASPENS guest authors Matthew B. Goren, MD, FACS, and Mark Gorovoy, MD, discuss the merits of each method. We hope you enjoy the discussion.
Kenneth A. Beckman, MD, FACS
OSN CEDARS/ASPENS Debates Editor
Anterior chamber IOLs work in suitable patients
Let me be blunt: There is absolutely nothing wrong with choosing a proper anterior chamber IOL when implanted correctly in an appropriately selected patient.
Anterior chamber lenses received a bad reputation, and rightly so, back in the 1970s and early 1980s when closed-loop IOLs were the style and mostly the only lenses available to surgeons. Perhaps the poster child of this lens was the Leiske lens. These lenses, because of their lack of flexibility, would wedge and erode into the anterior chamber angle and cause damage to the delicate structures with which they would interact. Uveitis-glaucoma-hyphema syndrome was commonplace with these lenses, and those of us who trained or practiced cornea and external disease in the 1990s have explanted thousands of these old-style IOLs. When I was a fellow at the Wills Eye Hospital in 1993, probably the most common surgical procedure we performed was penetrating keratoplasty with IOL exchange involving Leiske or other similar closed-loop IOLs.
However, the anterior chamber lenses of today are not your grandfather’s anterior chamber IOLs. Modern anterior chamber lenses are flexible and do not cause the problems of those previous models. Today’s anterior chamber IOLs are safe and well tolerated and, if placed correctly in patients without severe anterior segment disorganization, should be expected to last indefinitely without complication.
I have heard anecdotal reports from some naysayers that up to 50% of patients with modern anterior chamber IOLs develop complications. However, the literature suggests otherwise. Every cataract surgeon knows that, when confronted with the decision of whether to use a primary anterior chamber IOL or some other kind of non-capsular supported posterior chamber lens, the circumstances are difficult and the surgeon is stressed. The cataract surgery, which usually has progressed routinely, has encountered a complication, and the surgeon often wants to complete the surgery as soon as possible. This may result in inadequate vitrectomy, and when an anterior chamber IOL is used, a rushed insertion can result in bunching of the iris, iris capture or iris damage such as cyclodialysis or iridodialysis. The reported complications of anterior chamber lenses, in my opinion, are more often the result of the complicated surgery rather than the lens itself. When confronted with a case in which there is inadequate capsular support and the surgeon is uncomfortable utilizing a sutured, glued or other posterior chamber lens, a methodical and complete anterior vitrectomy followed by the careful placement of a properly sized anterior chamber IOL is absolutely appropriate. In such cases, it is likely that a subsequent complication such as corneal decompensation or glaucoma would have happened regardless of the type of IOL used. Complicated surgery has a higher rate of complications.
I have generally been reluctant to use anterior chamber IOLs in patients with severe glaucoma, chronic uveitis or anterior chamber disorganization. My concern is that a lens that interacts more with the anterior chamber angle structures and uvea would logically compromise these structures more, resulting in worse uveitis or glaucoma. However, the literature shows that even in some of these circumstances the outcomes of anterior chamber IOLs are excellent.
Surgeons come to the operating table with a range of skill sets and comfort levels with various techniques. There are certainly times when it can be argued that one technique is inappropriate for a given situation. For example, a patient with a history of severe anterior segment trauma and extensive loss of iris tissue with glaucoma would be better served with a posterior chamber lens. However, when confronted with a patient who lacks capsular support but has otherwise healthy anterior segment anatomy, there is no fault in choosing an anterior chamber IOL, assuming it is properly placed.
I have patients in my practice who were given anterior chamber IOLs both at the time of complicated cataract surgery as well as for secondary procedures who continue to do well without complications and with excellent vision 20+ years later. In fact, I struggle to remember a single patient whose open-loop anterior chamber IOL implanted by me had to be removed other than in cases of subsequent trauma.
There is a reason why the Leiske lens is no longer available. There is also a reason why open-loop anterior chamber IOLs are readily available. Like most things, if used properly in a suitable patient, they work.
- Suelves AM, et al. J Cataract Refract Surg. 2012;doi:10.1016/j.jcrs.2012.05.037.
- For more information:
- Matthew B. Goren, MD, FACS, can be reached at Goren Eye Associates, Two Prudential Plaza, Suite 3175, Chicago, IL 60601; email: email@example.com.
Disclosure: Goren reports no relevant financial disclosures.
Scleral-fixated posterior chamber IOLs are ideal choice
Every cataract surgeon will eventually have to deal with the acute and unanticipated loss of the capsular bag support system. The first priority is removal of lens material and anterior vitreous. The focus of my comments concerns the placement of an IOL — anterior chamber vs. posterior chamber IOL. No one would argue against the ease of an anterior chamber IOL over the complicated surgical gymnastics required for a scleral- or iris-fixated posterior chamber IOL. Numerous articles have not shown any clinical advantage of the posterior chamber IOL in these cases, mostly because of the higher complication rate in the posterior chamber IOL eyes. So why would any rational person argue against anterior chamber IOLs in these acute situations? The short answer: experience.
My 35-year surgical experience has biased me against all anterior chamber IOLs. I have extensive exposure to every one made. Too many are ticking anterior chamber segment bombs, even the Kelman one-piece designs. There are two sizes of anterior chamber IOLs: too small or too large. The first anterior chamber IOL approved in the U.S. was the rigid single-piece Choyce IOL. It appeared to cause less endothelial cell loss than the subsequent flexible anterior chamber IOL disasters, but it almost always rotated into one of the adjacent iridotomies, ovalized the pupil and was painful to eye touch. These issues led to the design of flexible anterior chamber IOLs. The flexible thin loop designs (Hessburg, Leiske, Azar, ORC Stableflex) thankfully have been removed from the market. Those designs are equivalent to placing a posterior chamber IOL in the anterior chamber (which I unfortunately still get referred). They destroy the endothelium along with causing cystoid macular edema and glaucoma. The only treatment is IOL explantation and cornea transplant if there is edema. Leaving the IOL alone, which can look benign, and trying topical treatment is not a viable option. Just replacing the cornea is also a poor option because the offending anterior chamber IOL will quickly destroy the new endothelium. These anterior chamber IOL designs did their damage quickly, often within months of the original cataract surgery.
The last and final anterior chamber IOL designs, the Kelman series, are more than 30 years old, with no new anterior chamber IOLs I am aware of in the pipeline. These are the only anterior chamber IOLs available, mostly in the four-foot plate design rather than the three-foot design (Omnifit). These IOLs have flexible solid footplates in a clever attempt to avoid the flaws of the prior designs. They are kinder but not benign to the endothelium. They often have the same symptom complex of the original flexible anterior chamber IOLs, namely bullous keratopathy, cystoid macular edema and glaucoma. At surgery, the footplates are often cocooned into the angle as dense as the flexible designs. They behave just like the flexible designs and cause the same havoc on the anterior segment. They require IOL exchange, which for me is a scleral-secured posterior chamber IOL and corneal transplant. As you can see, my negative anterior chamber IOL experience continues to this day, and that is why I would never put one in.
To be fair, I am the first to admit the surgical complexity of scleral-supported IOLs, whether sutured or scleral tunneled. They require pars plana vitrectomy skills. They are not typically done under topical anesthesia. The surgical risks are serious and include retinal detachment or future dislocation. These are not techniques for the occasional surgeon, no matter how skilled. However, too many anterior chamber IOLs have decreasing cell counts that will require corneal transplants (the National Eye Institute-funded Cornea Donor Study verified grafts with anterior chamber IOLs had significantly lower cell counts than those with posterior chamber IOLs). Most of my referrals for posterior chamber IOL complications are anatomical, such as dislocations, single-piece haptic-sulcus placement, uveitis-glaucoma-hyphema syndrome or unhappy multifocal exchanges. Without prior underlying endothelial damage, they categorically do not destroy endothelial cells and the cornea is not an issue. This is not the case with anterior chamber IOL referrals because they are not anatomical issues, but instead toxic issues because they chronically destroy corneal and trabecular cells. Another way to look at this endothelial toxicity issue is to recognize that in eyes without underlying endothelial disease, such as Fuchs’ dystrophy, the endothelium will last a lifetime (100-year-old patients still have clear corneas). Posterior chamber IOLs do not increase endothelial cell loss; only eyes with anterior chambers IOLs do. That is why I am still frequently referred eyes with bullous edema and anterior chamber IOLs and not eyes with posterior chamber IOLs without underlying corneal disease.
I would not recommend an anterior chamber IOL. If the surgeon is not experienced with scleral-fixated posterior chamber IOLs, I would leave the eye aphakic and refer to a specialist. In this discussion, I have left out iris-sutured posterior chamber IOLs and iris claw IOLs, both of which I have little experience with by choice, again based on my original bad experience with the original iris clip IOLs and my conversion to posterior chamber IOL scleral fixation more than 30 years ago.
- For more information:
- Mark Gorovoy, MD, can be reached at Gorovoy MD Eye Specialists, 12381 S. Cleveland Ave., Suite 300, Fort Myers, FL 33907; email: firstname.lastname@example.org.
Disclosure: Gorovoy reports no relevant financial disclosures.