POAG (Primary Open-Angle Glaucoma)
Primary open-angle glaucoma, POAG, continues to represent a significant public health problem. At least 2.25 million individuals in the United States 45 years of age or older are estimated to have this disease. POAG is currently the third leading cause of blindness worldwide following cataracts and trachoma.

The prevalence of POAG shows a strong racial disparity throughout the world with rates of disease almost 4 times higher among African Americans. Increasing age and family history are also strong risk factors. Individuals with diabetes mellitus and those with cardiovascular disease are also reported to have a higher incidence of POAG.

POAG is a chronic, slowly progressive optic neuropathy (the optic nerve is the structure that transmits information from the eye to the brain) characterized by atrophy and cupping of the optic nerve head, and is associated with characteristic patterns of visual field loss. (Angle closure glaucoma presents with severe pain and sudden, dramatic loss of vision). Intra ocular pressure (IOP) is the most common, and important factor causing disease, but reduced blood supply and abnormalities of axonal/ganglion cell (nerve cell) metabolism can also contribute. Although population studies have demonstrated a commonly accepted "normal IOP range" of 10-22mmHg, there are a number of shortcomings to depending on "numbers" alone for diagnosis. In fact, as many as 30-50% of individuals who are proven to have POAG, actually have initial screening IOP’s below 22mmHg. Therefore, although, elevated IOP is still considered a key risk factor for POAG, it is no longer considered essential to its diagnosis. The actual appearance of the optic nerve as viewed by the physician, along with interpretation of the visual field tests and Optical Coherence Tomography (O.C.T.), have now assumed the predominant role in diagnosis, and follow up for those undergoing therapy.

The insidious nature of POAG is that there are no symptoms until a good deal of vision has been lost. Thankfully with vigilance and proper care, the vast majority of patients retain useful vision for long periods of time!! The goal of current therapy is to preserve visual function by lowering IOP below a level that is likely to produce further damage to the optic nerve. This can be accomplished by using medical therapy i.e. eye drops/pills, or surgical therapy- i.e laser trabeculoplasty or trabeculectomy in the operating room. Ocular hypotensive agents include: Beta antagonists such as Timoptic; Miotic agents such as Pilocarpine; Carbonic anhydrase inhibitors such as Trusopt; Adrenergic agonists such as Alphagan; Prostaglandin analogues such as Xalatan, and various combinations. Whatever choice is made, the patient is always urged to inform their primary care physician as each therapy, medical and surgical, can have systemic ramifications!

The future looks bright as new therapies continue in development and new diagnostic tools are being tested such as the hunt for genetic markers. As with many other chronic diseases, however, vigilance is the key!