After eye surgery, what is the white booger that builds up at the corner of your eye?

Prednisolone: Usually this is the white drop (prednisolone/predforte) that leaves some residue behind. This is ok and will go away when you finish your drops.

Accumulation of medi: One of the most common eye drop given after eye surgery is a steroid drop called prednisilone acetate. This drop has a whitish participate which can often accumulate on the corner of the eye.