Cataract surgery advances improve outcomes for eyes with subluxated crystalline lens

February 15, 2006

Chicago—Management of the subluxated crystalline lens in eyes with profound zonular deficiency has been significantly advanced by developments in anterior segment techniques and new technology, explained Ike Ahmed, MD, at the annual meeting of the American Academy of Ophthalmology.

Chicago-Management of the subluxated crystalline lens in eyes with profound zonular deficiency has been significantly advanced by developments in anterior segment techniques and new technology, explained Ike Ahmed, MD, at the annual meeting of the American Academy of Ophthalmology.

"Using the scleral-sutured capsular tension ring (Cionni ring, Morcher) or Capsular Tension Segment (CTS, Morcher) combined with more aggressive anterior segment techniques, it is now possible to maintain the benefits of small-incision phacoemulsification surgery and foldable IOL technology for these challenging cases," said Dr. Ahmed, assistant professor of ophthalmology, University of Toronto, Ontario, Canada.

Although the availability of capsular tension rings (CTRs) has been a major step forward for facilitating surgery in eyes with mild zonular instability, use of the standard CTR alone is not sufficient when there is marked zonulopathy.

"In those situations, use of a modified CTR or CTS is needed because those devices are designed to allow scleral suture fixation and stability of the capsular zonular complex," Dr. Ahmed said.

The modified CTR is best implanted after lens removal and should not be used in eyes with a tear in the anterior or posterior capsule. It is available in two versions featuring one or two eyelets, respectively, to enable scleral suture fixation.

Designed by Dr. Ahmed, the CTS is a 120°, PMMA partial ring segment with a 5- to 5.5-mm radius of curvature. Depending on the extent of zonular deficiency, one or two segments are used. In contrast to the modified CTR, it can be placed after capsulorhexis to support the capsule over weakened zonules during phacoemulsification and can be used regardless of the integrity of the anterior or posterior capsules.

The CTS is designed with one hole for suture scleral fixation to address the need for long-term capsular bag centration in these eyes. In addition, to enhance support during lens removal, the CTS features an eyelet for insertion of an iris retractor.

"The CTS-iris retractor complex offers a safer alternative to the use of iris or capsular retractors for holding the capsulorhexis open during phacoemulsification," Dr. Ahmed said.

Once the segments are in place, a CTR is also introduced. Dr. Ahmed explained that while the CTS affords transverse support, the CTR will contribute circumferential support that will be important for long-term centration.

For CTS suturing, 9-0 Prolene or 8-0 Goretex have now replaced 10-0 Prolene, which had been recommended in the past.

"Our concern in these eyes is to avoid late suture breakage, and so our recommendation now is to use a more indestructible suture material," Dr. Ahmed concluded.