Glaucoma is an eye disease, which is one of the leading causes of blindness in the United States, yet when diagnosed early it is almost always preventable. Glaucoma is damage to the optic nerve caused by a variety of ocular conditions. Glaucoma was traditionally thought of as a pressure dependent disease and only patients with elevated eye pressure, greater than 21 were at risk for developing glaucoma.
Recently this theory has been proven inaccurate. Although, the majority of patients with glaucoma have high eye pressures, a small percentage of patients with normal eye pressure will develop glaucoma. Glaucoma damage results in permanent loss of vision, which can ultimately lead to total blindness if not treated. Early visual loss initially effects peripheral vision followed by central vision. This specific pattern of loss helps the ophthalmologist diagnose this vision threatening disease, but at the same time ongoing damage may go unnoticed.
The eye produces a clear fluid that inflates the eye and nurses many structures including the lens and the cornea. The pressure in the eye like any ball increases as the fluid or air is pumped in. Increasing eye pressure often results from a poorly functioning or blocked drain. The drain of the eye, called the trabecular meshwork, allows this fluid to return to the blood stream and keeps the eye pressure normal.
• Primary Open Angle Glaucoma (POAG): The most common form of glaucoma, 1% of all Americans will develop POAG in their lifetime. There are often no symptoms associated with the onset of POAG. Increasing eye pressure results from blockage or malfunction of the drain. Visually the drain appears normal.
• Chronic Angle Closure Glaucoma (CACG): Nearly half a million people in the United States suffer from CACG. People of Asian or Eskimo descent are at increased risk of developing this form of glaucoma. Like POAG damage may occur without symptoms. Abnormal positioned iris partially blockages the drain causing an increase in eye pressure.
• Acute Angle Closure Glaucoma: This symptomatic and dangerous form of glaucoma is due to acute blockage of the entire drain. Patients complain of blurred vision, halos around lights, severe pain, nausea and vomiting. The pressure may reach very high levels and treatment should be sought immediately. This form of glaucoma can cause severe vision loss in a short period of time.
• Pigmentary Glaucoma: This type of glaucoma is most common in near sighted men and women between the ages of 20 and 40. Pigment released from the iris clogs the drain and causes increased eye pressure.
• Exfoliation Glaucoma: This very prevalent form of glaucoma is more common in patients of European descent over the age of 55 years of age. The drain becomes blocked with exfoliative material causing an increase in pressure.
• Normal Tension Glaucoma: Glaucomatous damage occurring at normal eye pressure. This type of glaucoma is very difficult to treat and often requires extremely low pressure to prevent further damage. The lack of good blood flow or an extreme sensitivity to eye pressure are possible mechanisms of damage.