Surgeons explore new ways to address compromised capsular support
The trick is to make sure that whatever method is used, fixation points are exactly 180° apart.
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.
Managing IOLs in the eye with compromised capsular or zonular support has always been a concern for surgeons. While anterior chamber IOLs have been around for many years, and cumbersome suturing procedures have also been around for many years, there are now new options to manage these patients.
This month, Audrey R. Talley Rostov, MD, and Cathleen M. McCabe, MD, discuss their techniques for placing IOLs in eyes with compromised capsular or zonular support.
We hope you enjoy the discussion.
Kenneth A. Beckman, MD, FACS
OSN CEDARS/ASPENS Debates Editor
No one best method works for all weak zonules
There is no one best method for IOL fixation in cases of weak capsular support. Each surgeon should, at the end of the day, have in mind a method for providing a well-centered, functional IOL that provides a lasting solution for the patient’s vision.
Whatever the reason for the lack of capsular bag stability or missing zonules — genetic, congenital, trauma, iatrogenic — the surgeon should be prepared and have at least one “go-to” method for fixating an IOL when it cannot be implanted in the capsular bag.
In a complicated cataract surgery when a rent in the posterior capsule prevents implantation of the lens in the bag, for example, a decision would need to be made whether there is enough capsular support to fixate the lens in the sulcus. Sometimes there is, and the solution is easy. My preference here is to use a three-piece lens, which is easily sulcus-fixated. If there is good capsulorrhexis left, then optic capture with the three-piece IOL in the sulcus can help center the IOL.
If there is some decentration, then iris suturing the IOL can be helpful as well. Using the McCannel or modified McCannel type of suturing of the IOL to the iris at the mid-periphery minimizes pupil distortion. If the IOL in the sulcus is a little decentered, then using this suture of the haptic to the iris on one or both sides recenters the IOL.
Part of providing a lasting solution for the patient in these cases is choosing an appropriate IOL. Whether implanting a sulcus-based IOL, iris suturing an IOL or gluing an IOL, avoid the one-piece hydrophobic acrylic IOLs. These can cause iris chafing and result in UGH (uveitis-glaucoma- hyphema) syndrome. IOLs should be chosen carefully, knowing the benefits and limitations of any particular IOL for each particular method of securing the IOL.
Being prepared is important, especially going into surgery with the feeling or knowing that there will be issues with the capsule or zonules. If I am going to be doing a complex surgery, or if surgery becomes complex, I keep a separate tray of special instruments available. I think ahead, “What would I need in this or that situation?” I am always prepared for plan B.
Say the IOL is implanted in the sulcus, but it is a little askew and an iris suture is needed. A couple of the tools that I really like from MST include a micro-grasper, micro-forceps, as well as a micro-snare, which I have found invaluable for retrieving the suture when suturing the IOL to the iris. The micro-snare can go through a really small microincision, about 1.3 mm, and be used to grasp and draw out the suture to be tied externally. It is very handy for any kind of iris suturing or anytime you need to grasp a suture.
When I am in a situation in which the patient has had previous trauma or previous complex cataract surgery or previous retinal procedure, something where I know there is absolutely no capsular support whatsoever or there may be iris missing, then one of the methods I like to use is what has been popularized as the transscleral “glued” IOL technique. This is a fairly straightforward method of transscleral fixation of the IOL. I have done this very successfully, getting good IOL centration.
Here again IOL choice is important. The Zeiss Lucia three-piece IOL is well suited to this technique because of the haptic material; with other three-piece IOLs, sometimes the haptic breaks during the procedure. It is a disappointing day when half the IOL is in place with the haptic fixated and the other haptic breaks.
The keys that are mission critical for success are marking where the scleral flap will be developed and where the haptics will be placed, ensuring that the scleral-fixated haptics are indeed 180° apart. That way, the IOL will be nicely centered without any torque. The main things to do are to center the IOL and avoid torqueing the IOL. Rotation of the IOL can lead to astigmatism and multiple images.
- For more information:
- Audrey R. Talley Rostov, MD, can be reached at Northwest Eye Surgeons, 10330 Meridian Ave. N., Suite 370, Seattle, WA 98133; email: firstname.lastname@example.org.
Disclosure: Talley Rostov reports no relevant financial disclosures.
Centration is the big challenge
In cases when the zonules are not perfect but neither are they absent, there are steps to take to reinforce them without going to the “big guns” first.
If the zonules appear to be weak, the least invasive thing to do is to put in a capsular tension ring (CTR), an open loop of acrylic that stretches out and holds the capsular bag open, distributing those stresses that would normally be on the zonules more evenly, so that the strong zonules can support those that are weak.
If that option is not available, then a three-piece IOL could be implanted in the sulcus in front of the capsular bag, using optic capture through the anterior capsulotomy to center the lens.
When zonular weakness exceeds 3 to 4 clock hours, then a CTR with an eyelet or an Ahmed segment can be sutured to the eye wall. Or, if there is very little zonular support, then a CTR and two Ahmed segments 180° apart may be used.
When I know in advance that the case is going to be a little more complicated, then I ready a plan A, a plan B and a plan C. Plan A might be to put in a CTR and an Ahmed segment. Plan B might be to put in an iris suture or perform a Yamane technique. Plan C would be to secure the lens with Gore-Tex suture. As part of the planning, I would ensure the appropriate lenses and necessary tools were available.
In our OR, we keep a basket of emergency tools: CTR, Ahmed segment, CTR with eyelet, Gore-Tex sutures, 10-0 Prolene for iris suture, 9-0 Prolene for scleral suture, a thin-walled 30-gauge needle for the Yamane technique, little intraoperative forceps for intricate maneuvers, a Bonn hook and a Condon snare (MST). Additionally, we keep on hand Miochol (Bausch + Lomb) or Miostat (Alcon) to constrict the pupil when using an iris suture or to keep the IOL from moving forward after implantation in the sulcus.
Any of those techniques — iris fixation, scleral fixation, glued haptics, Yamane technique, Gore-Tex suture — can be used, even if there is not a single zonule available.
One great addition for me has been the use of the double-needle technique for iris suturing as described by John C. Hart, MD, FACS. This is a technique of passing the needle through the cornea, through the iris, under the haptic, back out through the iris and the cornea, and leaving the needle in place, allowing for another even more peripheral needle pass. This enables placement of the suture in the peripheral iris where it can support the lens without distorting the pupil, thus avoiding one of the risks associated with iris suturing.
Another innovative technique that can be done in place of adding Ahmed segments and CTRs is the Yamane technique. The advantage of this technique is that the conjunctiva is not removed from the sclera in order to place sutures.
The Yamane technique involves using a bent thin-walled 30-gauge needle to penetrate the sclera 180° apart, then a three-piece IOL haptic is threaded into that 30-gauge needle and externalized by removing the needle and the haptic from the sclera. The needle is passed through the conjunctiva and sclera in a tunnel manner, the haptic is engaged and externalized from the sclera and conjunctiva, and then low temperature cautery is used to melt the end of the haptic into a little mushroom top shape, or flange, which can then pass through the conjunctiva and into that scleral tunnel to support the lens. I use the Zeiss Lucia lens because it has a tough haptic that does not kink and it forms a nice flange with the low-temperature cautery. There is a bit of a learning curve, but it is a very straightforward procedure that has minimal impact on the conjunctiva.
One of the things to worry about with scleral-fixated lenses is the 9-0 Prolene suture degrading and breaking in the future. One technique that ameliorates that problem is Gore-Tex suture of a Bausch + Lomb Akreos AO60 lens. The lens has four closed-loop haptics, and because of that four-point fixation, the result is a nicely centered and secure fixation to the sclera. The Gore-Tex suture, which is used off-label, is desirable because it is long-lasting. The haptic does not degrade and the Gore-Tex suture does not degrade.
The technique with the AO60 requires taking down the conjunctiva from where the sutures are going to be placed and then placing two sets of two sclerotomies 2 mm apart and 2 mm posterior to the limbus. The two sets of sclerotomies are placed 180° apart. Gore-Tex suture is threaded through two haptics on each side of the IOL and then those ends are externalized through the sclerotomies and tied, with the knots buried in the sclerotomies, allowing for secure and easily centered fixation.
Centration is the big challenge. Even with four-point fixation, if the sclerotomies are not exactly 180° apart and the same distance from the limbus, the lens will not be centered; it will be tilted or off axis.
Finding a technique that is symmetric on either side that works for the surgeon consistently is the important thing. Becoming facile with one or two techniques will enable the surgeon to reliably center the implant and have it securely fixated. You do not have to know all of them, you just have to have a couple in your back pocket for when you need them.
- Double needle iris IOL fixation. https://www.aao.org/clinical-video/double-needle-iris-iol-fixation-2. Accessed Oct. 23, 2018.
- For more information:
- Cathleen M. McCabe, MD, can be reached at The Eye Associates, 6002 Pointe West Blvd, Bradenton, FL 34209; email: email@example.com.
Disclosure: McCabe reports she is a speaker and consultant for Alcon, Bausch + Lomb and Zeiss.