Ocular Disease: Glaucoma

It is a disease that causes damage to nerve fibers of the optic nerve and results in the formation of blind spots. Glaucoma is often associated with a high intraocular pressure (IOP), or pressure within the eye. In some cases, the disease may occur even in the presence of normal IOP and is referred to as normal (or low) tension glaucoma. Glaucoma is also one of the leading causes of preventable blindness in the United States.

There are several types of glaucoma. Two of the most common forms are open-angle and angle-closure glaucoma. Open-angle is the most common of all forms of glaucoma and is caused by a disruption in the normal flow of aqueous fluid that flows through the pupil and into the anterior chamber. The aqueous fluid is prevented from passing through the eye's filtration system (trabecular meshwork) and is prevented from draining from the anterior chamber. As fluid continues to accumulate, the intraocular pressure gradually increases. Over time, the optic nerve may become damaged and affect vision.

Angle-closure glaucoma is more rare than the open-angle form, but is more serious. This form is caused by a rapid increase in IOP that may lead to symptoms such as blurred vision and headaches. If not treated promptly it may lead to blindness.

Other types of glaucoma include:

• Normal (or low) tension glaucoma - type of glaucoma that does not involve an elevated IOP and, in fact, the pressure may appear normal. The exact cause is not known, but it is thought that poor circulation to the optic nerve may be a factor

• Childhood glaucoma - rare form of the disease that is genetically linked and generally affects children between infancy and adolescence. This form (as in the open-angle form) may appear asymptomatic, but if left untreated may result in vision loss.

• Congenital glaucoma - similar to Childhood Glaucoma, but symptoms are usually quite apparent.

• Secondary glaucoma - caused by complications of secondary medical conditions or diseases. It is often associated with eye surgery, cataracts, eye injuries, etc. Some of these forms include Pigmentary Glaucoma and Neovascular Glaucoma.

One of the reasons that glaucoma is so devastating is that the disease often does not present any symptoms until vision has already been damaged. "Silent thief of sight" is an apt and often used description for this disease.

• Ocular hypertension 
• Family history
• Age - risk increases as age increases
• Diabetes
• African-American heritage
• High myopia
• High hyperopia
• Eye surgery or injury
• Cardiovascular disease

Certain medications may be administered to help control glaucoma by either increasing the outflow of aqueous fluid or by decreasing the production of aqueous. Ointments, drops, pills, or tablets may be used to deliver the medication. As the disease progresses and in more severe cases, laser or conventional surgery may be necessary to drain fluid from the eye.

Unfortunately, there is no prevention or cure for glaucoma. The disease is treated most commonly with eye drops. More advanced cases may require pills or even surgery. The best way to prevent vision loss is through regular eye examinations.