Ultrasound biomicroscopy evaluation of pseudophakic pupillary block by vitreous prolapse after Nd:YAG laser posterior capsulotomy

Intraocular pressure rise is a common complication after neodymium:yttrium-aluminum-garnet (Nd-YAG) laser posterior capsulotomy. Although in most cases it is related to an inflammatory response, there are other possible mechanisms such as misdirection syndrome and pupillary block. The authors report two cases of pupillary block by vitreous prolapse after Nd-YAG laser posterior capsulotomy evaluated by ultrasound biomicroscopy (UBM). UBM allows to differentiate possible causes of intraocular pressure rising after laser capsulotomy even in cases of corneal opacity. It also allows to detect intraocular lens dislocation, sometimes associated with this situation. This is the first report that describes the characteristics of UBM images of this complication.