The primary purpose is to compare the effect of immediate therapy to lower the intraocular
pressure (IOP) versus late or no treatment on the progression of newly detected open-angle
glaucoma, as measured by increasing visual field loss and/or optic disc changes.
The secondary purposes are to determine the extent of IOP reduction attained by treatment, to
explore factors that may influence glaucoma progression, and to describe the natural history
of newly detected glaucoma.