Intra-Operative Posterior Capsule Laxity During Phacoemulsification And Management Strategies

We describe posterior capsule (PC) laxity observed during irrigation and aspiration (I/A) in cataract surgery. Normally, zonular support together with irrigation fluid dynamics maintain the PC in an upward concave configuration during I/A, providing counter-traction to facilitate efficient cortical clean-up. In the presence of a lax PC, there is an increased risk of posterior capsular rupture (PCR). Previous studies have reported that approximately 24% of PCRs occurred during I/A. Apart from a report by Ozcura et al. describing floppy PC during phacoemulsification in eyes with angle-closure glaucoma that had received preoperative (preop) intravenous mannitol, lax PC has not been widely described.

We report a series of cases in which a lax PC was noted intraoperatively. Our objective is to highlight the importance of recognising this during cataract surgery, and discuss the management strategies to minimize the risk of PCR and optimize surgical outcomes.

A 62-year-old lady with pseudoexfoliative syndrome and significant cataract underwent cataract surgery. No lens subluxation, phacodonesis, or asymmetrical anterior chamber depth were noted clinically preop to suggest zonular weakness. Ultrasound biomicroscopy (UBM) demonstrated zonular deficiency, evidenced by rounding of the lens profile at and posterior to the lens equator. Intraop during I/A, despite the aspiration port being slightly tilted off vertical, the PC was aspirated with star-fold lines. Aspiration was stopped immediately and PCR was averted. Another 70-year-old lady with ostensibly 'normal' age-related cataract and no preop signs of weak zonules, underwent routine cataract surgery. During I/A, the PC was highly mobile and followed the cortical material towards the aspiration port, with transient star-fold lines observed despite the port facing upwards. Low-vacuum capsular polishing was slow due to poor counter-traction. After IOL implantation, redundant PC folds were seen on intraop optical coherence tomography at the PC–IOL interface. During fellow eye surgery a week later, similar lax PC was observed. 2 straight traction lines were seen on aspiration of the inferior cortex with intraop OCT showing straightening and upward angulation of the PC. Following probe removal, the PC bowed upwards towards the corneal endothelium as the anterior chamber shallowed, necessitating gentle viscoelastic injection to restore its concave configuration prior to IOL implantation.

Awareness of a lax PC is essential, as it may predispose to PCR. Potential management strategies include performing preop UBM in cases with possible zonular weakness, gentle suction during I/A, and injecting viscoelastic to provide ballast for the PC. It may also be helpful to turn the irrigation and aspiration tip 90 degrees so that the stream of irrigation fluid pushes the PC backwards. Injection of a capsular tension ring to keep the PC taut is another option, although this may hinder aspiration of the cortical lens material. It is therefore important for cataract surgeons, especially ophthalmolgy residents embarking on their surgical training, to be cognizant of this entity to take necessary precautions to minimize intraop risks.