Eyeworld

EW CATARACT/IOL 52 March 2011 by Brock K. Bakewell, M.D. Dealing with zonular dehiscence Brock K. Bakewell, M.D., clinical assistant professor of ophthalmology, Univer- sity of Utah, Salt Lake City, discusses what to do when encountering loose zonules S urgeons may not be able to prevent zonular dehis- cence from occurring, but if it is anticipated early and dealt with properly, they can save themselves the trouble of dealing with a decentered or dis- located posterior chamber IOL in the future. Otherwise, additional surgery will be necessary to suture fixate the PC IOL. Therefore, if there is any zonular dehiscence at the time of cataract surgery, a capsular tension ring (CTR) should be placed in the capsu- lar bag. One of the most common causes of zonular dehiscence is pseu- doexfoliation. Extraocular trauma and surgical trauma are also fre- quent causes. In addition, zonular dehiscence can be brought on by ge- netic or congenital disorders such as Marfan syndrome. Certain patients are already set up for zonular dehiscence. For exam- ple, if pseudoexfoliation is observed upon examining the patient prior to cataract surgery, there should be a higher index of suspicion that zonu- lar problems may occur. If the pa- tient has had a retinal detachment and silicone oil was used to fix the detachment, the silicone oil can cer- tainly cause zonular dehiscence as well. When performing the pre-op slit lamp exam, surgeons must pay at- tention to whether the lens jiggles at all when the patient is instructed to move his or her eye back and forth. If the lens jiggles, that means the pa- tient has loose zonules and there is phacodonesis. Patients who have pre-op phacodonesis need a CTR. Often, however, surgeons may not discover phacodonesis until they are intraoperative. It may not be until they are removing some of the cortex that they notice it. They may pull out cortical lens material and then find that the bag is very loose in that certain meridian. Therefore, whenever I detect any weakness of the capsular bag I will go ahead and put a CTR in. Zonular dehiscence can even happen prior to a cataract. If a pa- tient has Marfan syndrome, the lens can become dislocated in the eye. The patient may have significant problems seeing because of a refrac- tive error that cannot be corrected by glasses or contacts. In this case, the patient might need to have a lens removal, even though he or she doesn't have a cataract, because of the dislocated lens. The techniques and tools for dealing with zonular dehiscence de- pend on how serious the problem is. The standard CTR is not meant to be suture fixated. It is placed in the capsular bag for zonular dehiscence up to 3 or 4 clock hours. However, some patients can have loss of a sig- nificant number of zonules. If there is significant zonular dehiscence, greater than 3 to 4 clock hours, a Cionni CTR should be used because this is designed for scleral suture fix- ation in order to secure the capsular bag. When using a one-loop Cionni CTR, my preferred method of inser- tion is an injector. When using an injector, it is not possible to com- pletely retract the one-loop Cionni. It can only be retracted up to the loop, so two-thirds to three- fourths of the ring can be retracted into the injector. I prefer this to manual insertion since the injector requires only one hand, which frees up the other hand for manipulating the leading eyelet of the ring with a Sinskey hook. I use the Sinskey hook to engage the leading eyelet of the Adjunctive surgical devices, such as dyes, pupil expansion rings, and capsu- lar rings and hooks, have added to the safety and efficacy of modern cataract surgery. Cases that were once ex- tremely difficult and challenging can now be addressed routinely with the use of these tools. In this month's col- umn, Brock Bakewell, M.D., reviews some of the issues regarding the use of capsular tension rings in the presence of zonular weakness or dehiscence. I found his insertion technique for the single-loop Cionni ring to be particularly valuable and look forward to trying it on my next ectopia lentis case. I hope you will find his review and discussion help- ful for your next case with loss of zonu- lar integrity. Richard Hoffman, M.D. Column Editor Cionni one-loop CTR in the eye Source: Brock K. Bakewell, M.D. Cionni one-loop CTR being inserted Source: Brock K. Bakewell, M.D.

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