YAG Peripheral Iridotomy or PI is performed by making a hole at the edge of the iris by a laser.  It is generally a safe procedure with good efficacy in the the prevention of pupil block from the crystalline or pseudophakic lens.  This video describes in-depth the technique for successful PI and how to minimise the risks for optimal outcome.  The various nuances of PI are subsequenbtly discussed in the 2 following videos.