Bean-shaped rings can be useful devices for implantation of “bag-in-the-lens in eyes with loose or no capsular support,” said Marie José B. Tassignon, MD, PhD.
San Diego-Bean-shaped rings can be useful devices for implantation of “bag-in-the-lens in eyes with loose or no capsular support,” said Marie José B. Tassignon, MD, PhD.
As she explained, the only “absolute contraindication” of the bag-in-the-lens technique she developed is where there is no capsular support in which to implant the lens, or where support is deemed insufficient for lens success, said Dr. Tassignon, Belgium, during the 2015 meeting of the American Society of Cataract and Refractive Surgery.
“With previous bag-in-the-lens implantations, I always used a lasso technique in the past,” she said, but noted potential risks included resorption of the thread over time.
The lens itself has a 5-mm central optic with elliptical flanged haptics on the anterior and posterior surfaces with the haptics oriented 90° to each other. However, the centration and rotational stability over time is heavily dependent upon capsule integrity.
To that end, Dr. Tassignon developed polymethyl methacrylate bean-shaped ring segments designed so that when the IOL is placed, the inner semicircle of the bean segment slot into the interhaptic groove of the bag-in-the-lens, providing additional support to the IOL, she said.
“When you’re positioning within the capsular bag, calculate the white-to-white, minus 1mm,” she said. “At one part, you’ll have the bean-shaped ring and the IOL.” A second bean-shaped ring can be used on the other side of the bag to center the lens even more.
“If you need a second one, calculate the white-to-white and add 1 mm,” she said.
Next: Study results
In her initial studies, 37 patients had both beans implanted in the sulcus, 9 patients had one bean in the sulcus, 5 patients were implanted with 2 beans in the capsule, and one patient was implanted with the absence of any capsule. In the latter of these, Dr. Tassignon performed a sulcus fixation and lassoed the IOL.
It was possible to implant the bag-in-the-lens in all cases, she said.
When there is bag remnant, the procedure adds minimal additional time to the procedure, she said.
“If there is no bag, it’s very challenging and time consuming,” she said.
To date, there has been no reported zonular dehiscence with the beans, Dr. Tassignon said.
In addition, while traditional capsular tension rings (CTR) allow for 3-4 clock hours of zonular support, the beans can offer as much as 6 clock hours.
In her published study, Dr. Tassignon et al. found with the bag-in-lens IOL, if there is mild capsular instability a CTR can be sufficient enough to provide a stable platform to allow for the safe insertion of the IOL. Once capsular instability is more severe, the CTR often cannot maintain the necessary support.
“The inner segments support and center the IOL,” she said, and if necessary, a second segment can further center the lens by being placed opposite the first segment.
“It provides a scaffold for the insertion and centration of this lens in complex, complicated cases,” she said.
During a question-and-answer period, she said that while she has not imaged the eyes with ultrasound biomicroscopy, “it’s a good idea and may be a better approach of measuring the eye to size the bean.”