Cataract Surgery is About to Get Safer
Surgeons explain how they plan to use capsular tension rings once the FDA grants an approval.

"They help a lot and hinder hardly ever." That's why, says Paul Koch, M.D., capsular tension rings (CTRs) are such a valuable tool for cataract surgeons. It's also why the FDA is likely to approve one soon. The StabilEyes CTR, which was developed by Ophtec and will be distributed in North America by AMO, will likely be the first approved.

StabilEyes will be indicated for use when weakened zonules are suspected or observed. Using a CTR may prevent complications such as lens subluxation into the vitreous, capsular tears, nucleus dislocation, and vitreous loss.

The StabilEyes system consists of a PMMA ring and a reusable inserter. The ring is placed in the capsular bag, maintaining the bag's integrity by circular expansion.

In cases of weakened or detached zonules, "It works like a Hula-Hoop," explains Frank Price, M.D. "When you push on one side, it moves the entire ring so that the tension is distributed 360 degrees along the remaining zonules, which prevents further dislodging of the other zonules."

The StabilEyes tension ring in the capsular bag.

Surgeons are Ready for an FDA Approval

Several surgeons spoke with Ophthalmology Management about how they plan to use the tension ring once it's approved. All said that they expect to use it in approximately 2% to 3% of their cataract procedures. They also said they expect it to become the gold standard of care in several types of cases, including traumatic cataract, pseudoexfoliation, and high myopia.

In addition, Robert Noecker, M.D., says he expects surgeons to use StabilEyes off-label for cases in which a soft IOL is implanted. "Because soft IOLs are so flexible, they are more prone to moving around during the procedure. CTRs help the IOL to stay central," he says.

Centration is also key for patients receiving multifocal IOLs. "It's imperative that the lens stay centered in order to avoid distortion of the patient's vision," says Dr. Koch. "Proper centration is an integral part of the procedure, and so the CTR can be as well."

The CTR can be implanted pre-emulsification or at any time after that during a cataract/IOL procedure. How the surgeon's usual technique is affected depends on the timing of the insertion. For example, as David Hardten, M.D., explains, in a loose-zonule case when the ring is inserted prior to cortex removal, it maintains outward pressure the surgeon can pull against to remove cortex. However, the ring can also trap cortex in the capsular bag, making the cortex harder to remove. "The cortex can sometimes be harder to get out, so, if the case is going well, wait until some cortex is removed," Dr. Hardten says. "Here, good hydrodissection is helpful."

Dr. Koch recommends using the inserter in all StabilEyes cases. "If you insert the ring manually," he says, "you have to stretch it out and sometimes guide it into the bag with two utensils. You have to be extremely careful in placing it, too. With the injector, the ring can be placed immediately. It's reliable, efficient and simpler."

Most surgeons are eagerly awaiting FDA approval of a CTR. Current FDA regulations require pre-approval for each use, which limits use to cases in which the need can be determined preoperatively. An approval would allow surgeons to have a capsular tension ring available for all cataract procedures, including when the need arises intraoperatively, enhancing their success rate.

Benefits Outweigh Risks

Few complications or post-op issues are anticipated once StabilEyes is available in the United States. In Europe, it has been used in 1% to 2% of cataract procedures since 1994. It's made of PMMA, a widely used material for ocular implants. "PMMA has a good reputation, so I can't think of anything that would be negative in the long-term," Dr. Price says.

"It's possible to cause dislocation of the ring into the vitreous, either by missing the fornix when placing the ring in an open-capsule situation, or perhaps after an early capsulotomy," Dr. Koch says. "But I haven't personally seen either of those happen." He also said a potential complication could be inadvertently placing the CTR anterior to the capsule, so that it rests in the sulcus rather than the bag. "This might cause ache or inflammation, or it could be completely innocuous. Again, I've never seen that happen."

Despite any minor problems that may arise, most surgeons agree that the capsular tension ring is a necessary option in cataract surgery. As Dr. Koch says, "They should have been on the market years ago."