The modern way of doing cataract surgery is to place the implant inside the clear bag that used to hold the cataract (this is a normal part of your eye). With time, this bag may become hazy. Also, some types of cataracts leave a haze on this bag at the time of surgery. The laser clears the haze to make sure you have the best possible vision. The haze does not return. You will need a driver for this appointment, as dilating drops will be used for the procedure.
There are no physical restrictions before or after the laser. It takes 30 seconds to 1 minute to do, and is painless.