SLT reduces IOP by around 30% when it is used as the first treatment. This is similar to IOP reduction of the most potent and widely prescribed class of glaucoma medicine (prostaglandin analogs). This effect can be lessened in the event that the patient is taking glaucoma medication. The effects typically last between 1 and 5 years, and in some instances, even longer than. If it doesn’t last at six to twelve months, it’s not considered to be successful.