The switch from large-incision manual extracap cataract surgery to smaller-incision phacoemulsification was helped tremendously by the advent of foldable IOLs. Back in the 1980s, phaco could be done through a 3 to 4 mm incision, but that would then have to be opened up to about 6 mm in order to allow insertion of a rigid PMMA IOL (polymethyl methacrylate).
To get IOLs with 6 mm optics through smaller incisions, the first advancement was the move to foldable IOLs as popularized by Thomas Mazzocco MD, which were implanted with lens-folding forceps. Next came injectable IOLs which allowed even smaller incisions and more consistent delivery. For many years the standard phaco tip size was about 3 mm because the injectors required that size for insertion. We have since moved to smaller incisions, between 2.2 and 2.8 mm for most cases and the smaller IOL injectors which match.
But in some cases we will have an IOL injector which requires a larger opening than the phaco incision. We have two options: we can enlarge the existing incision to accommodate the tip of the IOL injector cartridge, or we can use the wound-assist technique.
The wound-assist technique allows the un-enlarged phaco incision to act as an extension of the cartridge tip. We simply abut the tip of the injector to the phaco incision and then deliver the IOL. If you are using an injector which requires two hands (one hand holding the injector, the other hand on the screw-style pusher), it is normal for the eye to be pushed away from you and out of the primary position. Deliver the IOL into the anterior chamber and then use the chopper or other second instrument to place the optic and haptics into the capsular bag.
Click below for the wound assist technique and surgeon-loaded IOL injector:
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