Phaco Tip 143:
Chopper Induced PC Tear

A chopping instrument may tear the posterior capsule in one of two circumstances.

1. A sharp burr may develop on the instrument, especially if it has been traumatized by contact with a vibrating ultrasonic needle. It is therefore wise to examine the chopper beneath the microscope before it is inserted.
   
   
2. Even if the tip is smooth, a tear of the PC may result if a flaccid, wrinkled PC is engaged by the chopper and the chopper is subsequently moved. Such a dragging motion is capable of either disinserting the posterior capsule from its zonular attachment, or more likely creating a tear in the PC (essentially performing a posterior capsulorhexis). This undesirable series of events can occur if the chopper is being used to protect the posterior capsule, as it often is during the latter stages of nucleus removal, by positioning the instrument posterior to the nuclear fragment. If IOP declines as a result of nuclear segment removal i.e. a mini-surge occurs, the posterior capsule may move slightly forward and be engaged by the chopper. If at this moment the chopper is in motion, engagement of the somewhat flaccid posterior capsule may occur and a tear may result.

For the above reason, whenever a chopper is used to protect the posterior capsule it should remain motionless.

* Phaco Tip TM of Richard J. Mackool, M.D.

The parameters (instrument settings) and incision size presented here have been established by the surgeon and do not reflect recommendations by Alcon.