Variety of scleral fixation techniques can replace or rescue IOL

Welcome to another edition of CEDARS/ASPENS Debates. CEDARS/ASPENS is a society of cornea, cataract and refractive surgery specialists, here to discuss some of the latest hot topics in ophthalmology.

This month we are going to discuss scleral fixation as an alternative way of implanting an IOL when no capsular support is available or to rescue and recenter a dislocated IOL. Many valuable techniques for scleral fixation have been developed over the years, and each of them has undergone variations in the hands of experienced surgeons. Mitchell P. Weikert, MD, MS, will share tips and tricks from his vast experience with the Yamane technique, and Cathleen M. McCabe, MD, will describe her own belt loop technique. Learn and enjoy.

Kenneth A. Beckman, MD, FACS
OSN CEDARS/ASPENS Debates Editor

Yamane technique

Shin Yamane first presented the Yamane technique for flanged, intrascleral haptic fixation in 2016, and we had the opportunity to learn about it during the ASCRS Film Festival that year.

I was on the judging panel, and it was apparent right from the get-go that this was a breakthrough technique that would rapidly gain popularity. It is simple and logical on the surface, but the more you use it and the deeper you go, the more you realize that there are definite subtleties to it, small tweaks that can help and details that can make things more difficult.

For those who want to start using the Yamane technique, I always recommend first practicing on artificial eyes, such as SimulEYE. Skills transfer courses are also available at most major meetings. An important decision is which IOL to implant, given that none of the IOLs available are specifically designed for this off-label use. Virtually any current three-piece IOL can be (and has been) implanted via this technique. When choosing an IOL, the most important consideration is probably the haptic material. Polymethylmethacrylate (PMMA) is the most common, and because it is rather stiff and brittle, it is a little less forgiving when you are docking the haptics into the needles. It is used in the AcrySof platform (Alcon), the Tecnis (Johnson & Johnson), the SofPort (Bausch + Lomb) and the Light Adjustable Lens (RxSight). Polyvinylidene fluoride (PVDF), which is used for the CT Lucia IOL (Zeiss), is a tougher material and can withstand a lot of deformation and “inelegant” handling. It makes the surgery much easier, but the disadvantage is that the optic-haptic junction can be unstable, and sometimes the haptics may twist or disinsert from the optic. Another minor difference is the way the haptics melt to create the flange when cauterized. PMMA haptics melt in a wedge shape, whereas the PVDF haptics melt in a rivet shape. While this has minimal impact on the final outcome, I’ve found the PMMA haptics easier to embed in the sclera and try to avoid large flanges with PVDF haptics that have a tendency to sit on the scleral surface underneath the conjunctiva.

I typically use a 30-gauge TSK aesthetic needle (PRC-30013I) with a large internal lumen that makes it easier to dock the haptics. The needle position is critical, so take your time when you are marking the eye. I like to place two marks at the limbus, 180° apart, directly opposite to each other, using a Sinskey Hook or other straight instrument to ensure that I have an equal amount of cornea on each side of those two marks. Then I make two other marks, more posterior, 2.5 mm from the limbus in line with my limbal marks. Finally, I mark my needle entry points 2 mm away in a counterclockwise direction from those second marks. Accurate marking is the most critical step to ensure symmetrical haptic placement and to minimize the risk of IOL tilt or decentration.

When creating the incision for IOL insertion, I shift it a little bit to the left of the 180° meridian. I found that this makes the docking of the trailing haptic a little bit easier. Once the IOL is inserted into the eye, it is time to pass the needles through the sclera. This is the hardest part of the procedure to get consistent because it is essentially a blind pass — you cannot see where it is going. Infusion through an anterior chamber maintainer or pars plana approach is highly recommended because you need an eye that is adequately pressurized. I typically dock the leading haptic first starting with the needle in my left hand. Other surgeons may choose to start with the trailing haptic. The first needle is placed loosely on a non-Leur-locked Tb syringe. I like to approach the eye with the needle in my left hand at a 45° angle to the ocular surface. I embed the tip through the conjunctiva and into the superficial sclera. Then I use the embedded tip as a pivot point to flatten out before I advance my needle into the sclera, parallel to the limbus. I do that for about 1.5 mm until the bevel is completely within the sclera, and then I turn toward the mark at the limbus, angling slightly downward to enter behind the iris in the ciliary sulcus.

At this point, the leading haptic is threaded into the needle using a non-serrated microforceps, e.g. 25-gauge MaxGrip forceps, through a paracentesis to the right of the main incision. After the haptic is docked, I remove the needle from the syringe and let it rest on the ocular surface. The needle pass is repeated on the other side with the right hand. The trailing haptic is grasped with the microforceps, inserted through the main incision and docked into the other 30-gauge needle. The trailing haptic is then externalized and pulled thorough the sclera. I use tying forceps to grab the haptic and then perform low-temperature cautery to create the flange at its tip. I then externalize the leading haptic on the opposite side, create the flange, and then take time to make sure that both haptics look to be at the same angle relative to the limbus and at the same angle relative to the surface of the eye. If they are not symmetrical, the IOL is not going to be well positioned and is likely to tilt. If everything is in good order, I’ll advance each haptic little by little to ensure that the IOL stays centered. Once centration is verified, I will embed the tips of the haptics into the sclera, making sure that the conjunctiva remains free and mobile over them.

I also recommend an adequate vitrectomy before IOL implantation because you are passing the needles through the ciliary sulcus, which is near the vitreous base. I also recommend placement of two peripheral iridotomies. These can be created intraoperatively with a vitrector or postoperatively with a laser. Finally, I recommend monitoring the status of the retina with OCT to look for cystoid macular edema, especially if you are not achieving the postoperative vision that you expect.

If everything goes well, the Yamane technique is a safe, effective and fast way for secondary IOL implantation. With some experience, the procedure can be completed in about 15 minutes.

• For more information:
• Mitchell P. Weikert, MD, MS, a professor at Cullen Eye Institute, Baylor College of Medicine, Houston, can be reached at mweikert@bcm.edu.

Belt loop technique

The inspiration to develop the belt loop technique came from two women who were referred to me at around the same time in 2019.

They both had premium lenses that had decentered; one was a ReSTOR (Alcon) and the other was a Tecnis multifocal (Johnson & Johnson Vision). Traditionally, we would explant and replace the IOLs in these cases, but both my patients strongly wished to keep them. I started thinking of possible ways to reposition those lenses by using polypropylene sutures and melting them at the ends with low-temperature cautery, just like you do with the haptics in the Yamane technique. I discussed this option with both patients and said I would give it a try and then settle for lens replacement if it did not work. They were excited, and I scheduled both surgeries on the same day. It was a success: The IOLs were flat and well centered with no tilt and went back to functioning the way they did before the decentration.

The overall idea of the belt loop technique is to have a suture that goes from the conjunctiva through the sclera, around the IOL haptic, through the capsular bag, and then out through the sclera and conjunctiva again. Small flanges are then created at the end of the suture with handheld cautery, at the right tension to elevate the IOL in a planar fashion without tilt.

I start by cutting a 6-0 polypropylene suture and test it into the lumen of a 30-gauge long needle to make sure it passes easily before inserting the needle into the eye. Then I place two marks on the conjunctiva 2 mm posterior to the limbus, 180° apart, right at the points where I want to fixate the IOL. I bend the needle near the hub at a 90° angle and place it just posterior to the 2 mm mark on the conjunctiva, and I push it through the sclera with the longest tunnel I can make at an angle that is parallel to the iris. I watch the needle come behind the IOL haptic through the capsular bag, and then I grasp the end of it intraocularly and guide it out of a paracentesis on the other side of the cornea. Once the needle is externalized through the paracentesis, I use forceps to put the polypropylene suture into the lumen. I externalize it through the sclera by withdrawing the needle and then make a large flange, which I call a safety flange. A second needle, also bent at a 90° angle at the hub, is passed radial to the first pass just anterior to the 2 mm mark on the conjunctiva. I guide it under the iris but in front of the IOL-bag complex, externalizing it again through the same paracentesis. I take the opposite end of the polypropylene suture and introduce it into this second needle, also advancing it and externalizing it through the sclera, creating another large safety flange with low-temperature handheld cautery. I repeat the exact same thing on the opposite side. If the lens looks slightly decentered, which might be the case if the zonular support is weak or unbalanced, I gently pull and externalize more of the suture on either side, elevating the optic and watching for tilt until it comes right behind the iris in the proper location. At that point, I trim the suture by holding it with a little indentation into the sclera with fine forceps, leaving about 1 mm at the end and melting it with low-temperature cautery into a small flange. All flanges will then be buried with fine forceps into the superficial layers of the sclera. This is probably the most important step because we do not want the patient to be at risk for erosion of the flange in the future, which might lead to endophthalmitis. It is also critical to counsel patients not to rub their eyes. I believe that eye rubbing is frequently the cause of IOL decentration or dislocation to begin with, and when we reposition an IOL, it is important to remind these patients that it will not be a long-term solution if they are aggressively rubbing their eyes.

I have used the belt loop technique in many patients, and I would recommend it because it has many advantages as compared with IOL replacement. You preserve the lens that is already in the eye, no large incision or peritomy is needed, and you avoid the risks of lens replacement surgery. The beauty of it is that it works with any type of IOL, one piece or three piece.

• For more information:
• Cathleen M. McCabe, MD, chief medical officer at Eye Health America and medical director at The Eye Associates in Sarasota, Florida, can be reached at cmccabe13@hotmail.com.

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Sources/Disclosures

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Source:
Expert Submission

Disclosures:
McCabe reports consulting for Alcon, Bausch + Lomb and Carl Zeiss Meditec. Disclosure: Weikert reports consulting for Alcon and Carl Zeiss Meditec.

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