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Surgical management of cases with zonular dialysis and subluxated cataracts
The use of a capsular tension ring is helpful in these complicated cases.
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Capsular stability is an essential, required and integral part of safe modern-day cataract surgery. Any destabilization of the cataractous lens adds to the surgical challenge, and proper surgical planning is important for a successful outcome and optimal postoperative vision.
The development of the capsular tension ring (CTR) is a significant milestone in the history of cataract surgery. These devices help provide much-needed capsular stability to perform safe phacoemulsification and IOL implantation in difficult cases. While conventional CTRs help in cases of zonular weakness and rupture, they afford less or no protection in cases of advanced or progressive zonulopathy that can result in capsular decentration over time after surgery. In the subset of moderate to severe zonular compromise, the surgeon may consider using modified CTRs. Preoperative detection of zonular weakness during biomicroscopy will help prevent an intraoperative surprise and facilitate phacoemulsification.
In this column, Drs. Yuri Takhtaev and Sergey Takhtaev describe their surgical techniques and offer pearls in the management of zonular dialysis and subluxated cataracts.
Thomas “TJ” John, MD
OSN Surgical Maneuvers Editor
Capsular instability makes phacoemulsification a challenge even for an experienced surgeon. In everyday practice, we often manage cataracts with zonular weakness, and these patients can have different reasons for this condition. Whether it is due to trauma or severe pseudoexfoliation, an inherited systemic condition or accidental one-sided anomaly, it should be noted by a surgeon preoperatively, and one should choose the correct surgical plan.
Yuri Takhtaev
Having your surgical plan ready for safe manipulations during the surgical management of these more difficult cases is essential. Degree of zonular loss, its location and the presence of vitreous in the anterior chamber should be noted. For almost 15 years, working as a lector for a cataract wet lab post-graduate course in Saint Petersburg, Russia, I noticed that doctors coming from different regions face a different frequency of these conditions in their everyday practice. Congenital and associated systemic anomalies should make you aware of possible zonular insufficiency. However, some of these patients with zonular insufficiency are likely to have only eye-targeted symptoms and signs. Others, such as in Marfan syndrome, have a specific appearance.
Ultrasound biomicroscopy and anterior segment OCT are especially useful for zonular and angle assessment in cases in which the pupil fails to dilate. Making your surgical plan for such cases should include the possibility of CTR use, IOL suturing or intracapsular cataract extraction for severe cases. On biomicroscopy, an inferior subluxation often indicates 360° of zonular insufficiency combined with the effect of gravity. Gonioscopy is performed to note pseudoexfoliative material, any defects secondary to trauma or other signs of sequelae to subluxation. B-scan ultrasonography is indicated in opaque ocular pathology. Retinal detachments occur in 10% of eyes with Marfan syndrome and homocystinuria.
Techniques
Capsular instability often makes it a challenge to perform a continuous curvilinear capsulorrhexis. I would recommend using forceps rather than a cystotome, but it is always a personal choice. If started in the area of intact zonules, you can usually make a required diameter opening in the anterior capsule, if the defect does not extend 6 clock hours. Insert the CTR between the peripheral capsular bag and remaining lenticular material to prevent entrapment of cortex under the CTR. Hydrodissection is important in this case to provide free space for the CTR peripheral to the cortex. The cannula should be inserted in the direction of the dialysis to avoid enlarging it. The goal is to keep the remaining zonules for safe nucleus removal.
Marfan syndrome eye, severe pseudoexfoliation, microphakia, lens coloboma.
Images:Takhtaev Y, Takhtaev S
Severity of lens subluxation.
CTR implantation.
Cannula position during hydrodissection.
Modified CTR in capsular bag.
I prefer implanting the CTR immediately after creating the capsulorrhexis to support the fornix of the capsular bag during further manipulations. In severe cases, a modified CTR with scleral fixation is used, and phaco is continued. IOL implantation is safe with this technique, and good IOL stability is usually obtained. If capsular retractors were used for capsular stability and the CTR was not sutured, IOL suturing may be necessary. The CTR is usually inserted using forceps or a specially designed injector. A “fishtail” technique can also be used to insert the CTR, in which both its ends are held with forceps in a crossed manner to create a central closed loop that is placed in the capsular bag in the area of zonular dehiscence. Different chopping techniques should be considered instead of the usual tunnel grooving to avoid zonular stress during nucleus removal. IOL stability in both frontal and sagittal planes must be confirmed at the end of the surgery after viscoelastic removal. If this fails and you see pseudophakodonesis, suturing a haptic to the sulcus or iris is necessary.
Conclusions
Some pearls can be especially helpful in your first complicated cases. Incisions should be preferably away from the area of zonular weakness. Use high molecular weight viscoelastic. The capsulorrhexis should be initiated in an area away from the zonular dialysis. The capsulorrhexis is more easily performed with forceps than with a cystotome and should be made off-center in an eye with significant lens subluxation. The partial-thickness scleral flaps for a Cionni ring or IOL scleral fixation should be dissected before opening the main wound.
With modern technology, you can offer a safe and secure phacoemulsification procedure even for patients with complicated cases.
References:
Agarwal A, et al. Phacoemulsification. 3rd ed. SLACK Incorporated; 2004.Buratto L, et al. Cataract Surgery in Complicated Cases. SLACK Incorporated; 2013.
Cionni RJ, et al. J Cataract Refract Surg. 1998;doi:10.1016/S0886-3350(98)80218-6.
Vasavada AR, et al. Am J Ophthalmol. 2012;doi:10.1016/j.ajo.2011.11.012.
For more information:
Yuri Takhtaev, MD, is a professor and head of the ophthalmology department of North-Western State Medical University, Saint Petersburg, Russia. He can be reached at email: ytakhtaev@hotmail.com.Sergey Takhtaev, MD, is of Fyodorov “Eye Microsurgery” State Institute, Saint Petersburg branch. He can be reached at email: stakhtaev@hotmail.com.
Disclosure: Yuri Takhtaev, Sergey Takhtaev and John report no relevant financial disclosures.