There is a lot to learn from this resident cataract surgery. The case starts out with a reasonable pupil of about 5 mm in diameter. This is further expanded with gentle visco-mydriasis. During capsulorhexis creation the pupil becomes a little smaller, but the main issues compound when there is iris prolapse during hydro-dissection. The crucial error, however, is when the phaco probe is allowed to push into the iris stroma, dragging it. This then causes further pupil constriction which makes the rest of the case far more challenging.
Click to learn what went wrong and how to still successfully finish this case: