June 2008

 

CATARACT/ IOL

 

New device now in the ring


by Maxine Lipner Senior EyeWorld Contributing Editor

   

Innovative prototype promises to improve cortical cleanup

The H caspular tension ring has eight indentations to aid in cortical clean-up Source: Bonnie A. Henderson, M.D.

For patients with weak zonules, whether it be from conditions such as pseudoexfoliation syndrome or trauma, capsular tension rings (CTRs) can prove vital. The drawback to using these is that it can be difficult to perform adequate cortical cleanup with such a ring in place. Now a newly designed prototype, dubbed the Henderson capsular tension ring (HCTR, Morcher, Stuttgart, Germany), promises to change all that.

Innovative new design

This new HCTR is a modification of the traditional 14C Morcher ring (Morcher). The ring still has an open “C” shape and is composed of polymethylmethacrylate (PMMA). “The biggest modification is that the ring has eight indentations, equally spaced, that allow for easier removal of cortical or lenticular material that’s still remaining when the ring is placed,” said Bonnie A. Henderson, M.D., assistant clinical professor, Harvard Medical School, Boston. Dr. Henderson opted to redesign the traditional capsular tension ring to help alleviate the difficulties with cortical cleanup that appeared to plague some practitioners. “Surgeons noticed that after implanting the traditional rings, that it was difficult to remove any tissue that was still remaining because the ring compressed the residual material against the capsular bag,” she said. Dr. Henderson felt that a change in the ring design could help. “I thought that there has got to be a better way to stabilize the capsular bag and at the same time improve the ease of removing the cortical material,” she said.

The Henderson capsular tension ring itself is inserted much the same way as the traditional CTR. “This modified ring can be inserted manually, or it can be injected with the currently available injector systems,” Dr. Henderson said. “It inserts just as easily as with any traditional capsular tension ring.”

To enjoy all of the benefits of the ring, practitioners can rotate it after implantation. “Another feature of this ring is that because it has indentations, you can remove the cortical material under the indented portions then rotate the ring, so that the unindented portions become the indented portions. By doing this, the rest of the cortical material can be mobilized and removed more easily.” Dr. Henderson said.

Studying outcomes

Outcomes with the new ring, which has been tested in pig eyes, have been promising. In a recent blind, prospective trial investigators monitored parameters such as surgical and phacoemulsification time and the amount of BSS used for the procedure. In the study, which was published in the October 2007 issue of the Journal of Cataract & Refractive Surgery, one surgeon would implant one of three capsular tension rings and then just before the nucleus was removed, or the cortex or the IOL, the second surgeon who was masked to the initial procedure would step in. The three rings used included a StabilEyes (Advanced Medical Optics, Santa Ana, Calif.) capsular tension ring, a Morcher 14C CTR, or an HCTR (four eyes). “What we found was that there was a significantly lower amount of phaco time and fluid volume that was needed in the group that received the HCTR. Needed phaco time with the HCTR was just 86 seconds versus 147 seconds for non-Hcapsular tension rings. In addition, an irrigation volume of 75 cc compared with 191 ccs for non-HCTRs was needed. Overall, the average surgical time needed with the new device was just 3.5 minutes, compared with eight minutes for the traditional rings. Using the new HCTR is as easy as any other such device. “No modifications need to be done surgically at all,” Dr. Henderson said. “The key is to be able to successfully diagnose that there is zonular weakness and to place the ring early enough to stabilize the eye and finish the surgery without complications.”

In the United States, the HCTR is not yet available. “The ring has been under review [by the Food and Drug Administration] for at least a year,” she said. “It is, however, available in Europe and is the number one leading ring being sold in Sweden.”

For the future, Dr. Henderson continues to look for new ways to improve the technology. “Thomas Oetting, M.D., [University of Iowa, Iowa City] and I are working on another modification of this ring,” she said. “We’re hopeful that further modifications will continue to improve safety and efficacy.”

Editors’ note: Dr. Henderson has no financial interests related to her comments.

Contact Information

Henderson: 781-487-2200, ext. 3321, bahenderson@eyeboston.com

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