What are the stages of glaucoma?

Spectrum: It can be divided into pre-perimetric disease (before anything shows up on visual field testing), and perimetry disease (once you have visual field abnormalities), and at that point glaucoma can be divided into mild, moderate, and severe based on how abnormal the field is. Usually it's end stage when central vision is also diminished.

Continuum: The glaucoma continuum has been proposed to describe the stages. Structure and function are mentioned. Early on, structural damage to the optic nerves occur without functional vision loss . As the disease progresses, visual deficits occur.