Often slow. Glaucoma progression is often slow hence the low rates of being noticed by patients . Some forms can be quite rapid however . It really depends on the type of glaucoma and the individual characteristics of the patient.
Variable. Asymptomatic at first, classically peripheral vision is lost first, but paracentral vision can also be affected early. Usually only advanced disease really affects the sharpness of vision. The higher the pressure, oftentimes the faster the progression once glaucoma is diagnosed and followed.