Stepwise Management of Zonular Instability
A practical intraoperative sequence for restoring capsular stability while minimizing additional zonular stress.
J. Morgan Micheletti, MD, FACS, and Evan Dackowski, MD
Cataract and Refractive Surgery Today 
KEY TAKEAWAYS Zonular instability turns routine cataract maneuvers into stress tests for the capsular bag, so stabilization should precede rotation, chopping, and cortical removal Small, repeated ophthalmic viscosurgical device additions and capsule retractors can restore chamber control and capsular centration without abruptly deepening the anterior chamber Horizontal chop, tangential rotation, bimanual cortical cleanup, and timed capsular tension ring or segment placement reduce zonular stress while preserving fixation options Zonular instability during cataract surgery exists on a spectrum that ranges from diffuse weakness to focal or extensive dialysis. Regardless of the etiology, once instability is present, even routine maneuvers such as nuclear rotation and cortical removal can place additional stress on the remaining zonules. When we encounter zonular instability, we slow down and stabilize the capsular bag before proceeding. Rather than rely on a single maneuver or device, we manage these cases in a deliberate sequence that progressively restores capsular stability while minimizing additional zonular stress. RECOGNIZING INSTABILITY Zonular instability may be recognized preoperatively or discovered intraoperatively. Preoperative Recognition In select eyes with preexisting dialysis or zonular instability, we consider performing the capsulotomy with a femtosecond laser because it can create a centered, reproducible opening without relying on zonular countertraction, which can be helpful when the capsule is unstable. Intraoperative Recognition and Capsulorhexis Strategy Sometimes, zonular instability becomes apparent intraoperatively—often during the capsulorhexis. In these eyes, the capsule frequently moves with the tearing force because the zonules cannot provide adequate countertraction. The capsulorhexis may be smaller than intended because the capsule follows the vector of the tear. We try to maintain chamber stability with an OVD, frequently regrasp the capsule with forceps, and deliberately direct the tear outward to compensate for this tendency.
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