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Iris hooks can support loose nuclei
Once capsular fibrosis develops, dislocated lenses and capsular rings can be sutured to the sclera without risking capsular tears.
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MUNICH, Germany — In addition to their normal applications, iris retractors can be used to help stabilize the lens during cataract surgery in patients with pseudoexfoliation syndrome, according to a speaker here.
Charlotta Zetterstrom, MD, of St. Erik’s Eye Hospital in Stockholm, discussed indications and use of iris retractors at the European Society of Cataract and Refractive Surgeons meeting.
She said eyes with advanced cases of pseudoexfoliation syndrome usually have small, hard-to-dilate pupils. These patients are also predisposed to glaucoma, and long-term use of miotic glaucoma drugs leads to pupil atrophy.
For such cases, iris retractors can be used to expand the pupil, which makes the creation of a round, centered anterior capsulorrhexis easier, she said. A dye can also be used to stain the capsule and improve visualization, reducing the risk of tears, she added.
Dr. Zetterstrom said that eyes with pseudoexfoliation syndrome sometimes also have zonular dialysis, significant zonular weakness and phacodonesis. These can be identified preoperatively by increases or decreases in anterior chamber depth or during creation of the capsulorrhexis, when folds, wrinkles and movements in the anterior capsule are seen.
In such eyes, phacoemulsification can be difficult and can lead to lens decentration or late IOL decentration.
“In these cases, a good help is moving the iris retractors to the anterior rhexis. This maneuver keeps the lens in place during the surgical procedure,” she said.
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| (Photos courtesy of Charlotta Zetterstrom, MD.) | |
Zonular support
Dr. Zetterstrom said that iris retractors, usually four, are first placed in the pupil before performing the capsulorrhexis. If the lens has poor stability, the retractors can then be moved to the rhexis before proceeding with phaco.
| Capsulorrhexis size |
| According to Charlotta Zetterstrom, MD, the capsulorrhexis created in eyes with pseudoexfoliation syndrome should be large enough to allow adequate nucleus removal. However, the rhexis should not be larger than the diameter of the IOL optic, she said. Sufficient tissue must remain for fibrosis to develop around the optic, which decreases the postop formation of posterior capsular opacification, she said. |
She said the iris retractors should be soft, but several are available that would work for the technique. However, she said the capsulorrhexis must be round and without tears.
With a mobile nucleus and epinucleus, the lens material can then be removed using standard phaco techniques. A foldable IOL and capsular tension ring can then be implanted in the capsular bag, she said.
Dr. Zetterstrom said that because such eyes have poor capsular support, the capsular tension ring helps to maintain lens positioning.
She noted that eyes with pseudoexfoliation syndrome have a higher incidence of both open-angle and closed-angle glaucoma, making angle-supported anterior chamber IOLs a poor choice, “particularly if the surgical procedure has been complicated with vitreous loss,” she said.
Dr. Zetterstrom said she prefers to use a single-piece AcrySof IOL (Alcon) with a 6-mm optic and a sharp-edge design.
Lens dislocation
Dr. Zetterstrom said there will be some cases of postop IOL and capsular ring dislocation, sometimes years after initial surgery. However, if a capsular tension ring is used, it is possible to suture that ring and the IOL to the sclera in a second procedure. For this, Dr. Zetterstrom said she would suture the ring and lens to the sclera 2 mm from the limbus using a 10-0 polypropylene suture.
She said the capsule develops fibrosis several months after the initial surgery, making it safe for a suture to pass through the capsule without the risk of tears.
“A better and safer treatment option today is to use the Cionni modified scleral ring, which could be sutured to the sclera during the primary intervention without penetrating the capsular bag, thus avoiding tears in the capsule,” she said.
The Cionni ring has a hook containing an eyelet, which is placed above the capsule and sutured to the sclera, she said.
For Your Information:
- Charlotta Zetterstrom, MD, can be reached at St. Erik’s Eye Hospital, SE-112 82, Stockholm, Sweden; 46-8-672-3021; fax: 46-8-651-0785; e-mail: charlotta.zetterstrom@sankterik.se.