A retained lens fragment is common in cataract surgery because we are breaking up the cataract into many smaller pieces in order to aspirate them via a small incision. This means that occasionally, we will have a small lens fragment retained after cataract surgery and these tend to present on post-op day 1. This case has a retained lens fragment, but it is very difficult to see it. The quiz for you is to determine where it is hiding — look carefully! There are techniques such as using a high flow rate for viscoelastic removal or even doing the angle sweep technique to help minimize the chances of a retained lens fragment, but this still does not make it a zero occurrence event. Let me know in the comments section at which point in the video you notice the hiding piece of lens material.