In Part 4 of the Vit-Buckle Society’s Virtual Series, Gabriela LópezCarasa, MD, presented a secondary IOL implantation technique. The technique she elegantly described was one inspired by the technique of scleral fixation without conjunctival dissection to prevent suture erosion, originally described by Richard S. Hoffman, MD. In addition to Dr. Hoffman’s scleral pockets, she integrated a cow-hitch knot to provide two-point fixation and prevent lens tilt.
Camila V. Ventura, MD, PhD: Please briefly describe the secondary IOL implantation technique you chose for this case (Video).
Gabriela LópezCarasa, MD: The first step is to create the scleral pockets. I start by making clear corneal incisions 180° apart using a diamond knife, which will facilitate proper final positioning of the IOL haptics. Then, scleral pockets are created extending 3 mm posteriorly from the clear corneal incision using a crescent blade (Figure 1).
After placing a 23-gauge infusion cannula, I create a 7-mm sclerocorneal incision, and sutures are preplaced in the wound prior to fixating the IOL to avoid hypotony.
A 10-0 nylon suture and a 30-gauge needle are used to create sclerotomies 2 mm apart from each other in order to externalize the Gore-Tex CV-8 (polytetrafluoroethylene [PTFE], W.L. Gore & Associates) suture. The 30-gauge needle is used for docking the nylon suture, which is knotted at both ends to be used as a loop for placing the PTFE suture.
The PTFE suture is then pulled through the sclerotomy using the 30-gauge needle, 3 mm from the limbus. The nylon suture is externalized, either with a hook or forceps, to make a loop so that I can pull the PTFE suture out from the sclera with the nylon suture. The same steps are repeated for the other end of the PTFE suture.
For the cow-hitch knot, I use the same 10-0 nylon suture. First, both ends are passed through the eyelets of the IOL haptics. Then the PTFE suture is passed into the nylon loop and pulled through the eyelet to anchor the PTFE loop and create a two-point fixation knot on the haptics (Figure 2).
Figure 2. For the cow-hitch knot, both ends of the nylon suture are passed through the eyelets of the IOL haptics. Then the PTFE suture is passed into the nylon loop and pulled through the eyelet to anchor the PTFE loop and create a two-point fixation knot on the haptics
The IOL is then placed into the eye, and the sutures are pulled to position the IOL behind the iris and into the ciliary sulcus. My IOL preference for this technique is the one-piece CZ70BD IOL (Alcon), but an AcrySof MA60 IOL (Alcon) also works well.
After IOL placement, the PTFE sutures are retrieved from the scleral pocket with a Sinskey hook to externalize both ends, and a 3-1-1 knot is made and placed under the scleral pocket roof. Finally, the sclerocorneal wound is closed.
Dr. Ventura: What are the potential advantages and pitfalls of this technique?
Dr. LópezCarasa: The most significant advantage of the scleral pocket technique is the reduction of surgical time because there is no need for conjunctival dissection and scleral flap creation. The technique also avoids the induced astigmatism usually observed with a scleral flap technique. Moreover, by creating scleral pockets you prevent exposure and erosion of the suture, reducing the incidence of IOL displacement, luxation, and endophthalmitis.
The biggest pitfall with this technique is the possibility of not forming the scleral pockets correctly in size, depth, and length. This initial step requires attention and precision to avoid complications such as perforation of the sclera, bleeding, creation of a superficial scleral pocket, and malpositioning of the IOL.
Dr. Ventura: What pearls can you offer for making this technique go as smoothly as it appears in your video?
Dr. LópezCarasa: My suggestions are as follows:
- Review the technique and watch surgical videos to get yourself ready for surgery.
- Before you begin the surgery, make sure you have everything you need handy, including a diamond knife, crescent blade, 30-gauge needle, 10-0 nylon and PTFE sutures, and a Sinskey hook.
- The depth of the clear corneal incision must be between 300 and 400 µm.
- As you create the scleral pocket with the crescent blade, make sure you dissect the sclera moving the blade from side to side in a downhill movement.
- Avoid creating the scleral pockets at the 3 and 9 clock positions to prevent damaging the long posterior ciliary arteries.
- The scleral pockets should be at least 3 mm long to position the IOL behind the iris and in the posterior chamber.
- When you perform the sclerotomies to externalize the PTFE sutures, make sure the sutures traverse the pockets before continuing with the procedure.
- Using a 30-gauge needle to perform the sclerotomies, you will prevent leakage.
Dr. Ventura: Why do you choose this technique over others, or are there certain circumstances in which you like it better?
Dr. LópezCarasa: I want to emphasize that the best surgical technique is the one that works for you. That being said, I think this is a very sophisticated technique for secondary IOL implantation. Although I consider it challenging, great results can be achieved if you train and practice enough. Given that it prevents suture erosion and provides outstanding stabilization for the IOL, this technique can yield excellent visual results for patients without capsular support.
Dr. LópezCarasa wishes to thank Alejandro Lichtinger, MD, for educating and assisting her on the surgery discussed in this article.