The hole in the iris is known as an iridotomy. The iridotomy allows the flow of fluid to the front of the eye to be restored. Final hole in iris to release pressure in eye. With fluid passing through the iridotomy, the iris is no longer pushed forward. Fluid can leave the eye through the trabecular meshwork again.
Lasers deliver a type of light energy.
This type of light energy is similar to using a magnifying glass to harness the energy of the sun to burn a hole in a piece of paper on a sunny day. The magnifying glass needs to properly focus the light to create a hole in the paper. Likewise, if the laser is not aimed properly at the iris, there is no effect. In order to focus the laser, your eye doctor uses an instrument called a slit-lamp. This is the same instrument which is used to routinely examine your eyes.