Glaucoma is an optic neuropathy associated with visual field loss resulting from intraocular pressures (IOPs) which are too high for a particular optic nerve.  The “normal” range for IOP is 10 to 21 mmHg.  Since IOP is different for every individual and affects each individual’s optic nerve differently, some nerves may indeed have glaucoma in the setting of an IOP in the “normal” range. 

Although there are various etiologies of glaucoma (some genetic, some anatomic, and some idiopathic in nature), the end result is the same—damage to the optic nerve.  The visual field loss in glaucomatous optic neuropathy is typically peripheral initially, then encroaches on the central vision and can eventually result in blindness.  As glaucoma is an optic neuropathy, it by definition causes death of axons in the optic nerve; at this point we are not able regenerate nerve tissue, so this damage is permanent.

How is glaucoma treated?

Glaucoma is usually initially treated with eye drops to lower the IOP in order to preserve the remainder of optic nerve.  There are several classes of eye drops that can be used, which work synergistically together via different mechanisms.  If drops do not work or an individual does not tolerate them, then surgery is the next option.  Laser surgeries to the outflow portion of the eye, called the trabecular meshwork, can be attempted in certain types of glaucoma with varying success; your physician can help determine if you are a good candidate or not.  There are also surgeries where alternate modes of drainage of fluid from the eye are created to lower the pressure, some use a tube with a reservoir and others create a fistula into the eye and a space where fluid can collect under the conjunctiva, which is called a bleb.

It is important to understand that glaucoma treatments can NOT improve an individual’s vision, but aim to preserve what is left of the optic nerve and thereby to prevent further loss of an individual’s field of vision.