GLAUCOMA

In general, the true causes of glaucoma are not very well understood. While there is still much to learn, we do know that glaucoma has the potential to irreversibly rob a person of sight in the affected eye(s). The vast majority of glaucomas are slow in their progression and can take many years to cause noticeable vision loss, making early detection very important. Typically, there are no symptoms or obvious signs, but all of the eye doctors at the Advanced Center for Eyecare are trained and licensed to detect, treat, and manage common types of glaucoma. Because of the uncertainty around what causes of glaucoma, it can sometimes be difficult to determine if someone truly has glaucoma or if they merely are at risk for developing the disease. A comprehensive dilated eye exam can help an optometrist or ophthalmologist determine if further testing or treatment is necessary.

Glaucoma is a group of diseases that can damage the eye’s optic nerve and result in vision loss and blindness. The various forms of this disease include:

• • • • Primary Open-Angle Glaucoma
      • Angle-Closure Glaucoma
      • Normal-Tension Glaucoma
      • Secondary Glaucoma

Primary Open-Angle Glaucoma

This is by far the most common type of glaucoma and is generally associated with high eye pressure building up inside the eye, which is normally not perceived by the person affected. In a healthy eye, nourishing fluid is produced in an area of the eye at the base of the iris. This fluid then flows through the pupil and drains from the eye through a spongy meshwork near the front of the eye that leads to an opening where the cornea and iris meet, called the “angle”. This fluid may also be drained through a special pathway called the uveoscleral outflow. When there is a problem with overproduction of this fluid or insufficient drainage through the usual pathways, pressure can build up either slowly over time or quickly, which in turn can damage the optic nerve.

Unfortunately, there is no cure for open-angle glaucoma. In some cases, however, treatment can lower the pressure inside the eye enough to significantly slow the progression of the disease and prevent major vision loss. It is very likely that an annual comprehensive eye exam can help detect even early stages of glaucoma, allowing the eye doctor to catch preventable vision loss.

Angle-Closure Glaucoma

This more rare form of glaucoma is also known as narrow-angle glaucoma or acute glaucoma, due to its rapid onset. Angle-closure glaucoma is often caused by a sudden complete or partial blockage of the eyes drainage canals, which can cause a rapid increase in intraocular pressure. This form of glaucoma is often accompanied by symptoms such as headaches, eye pain, nausea, rainbows around lights at night, and very blurred vision.

Angle-closure glaucoma can usually be treated with surgery to unblock the drainage canals, depending on the anatomy of the patient. For most people, this surgery is very successful and long-lasting. Having regular checkups is still important though because a chronic form of glaucoma could still occur.

Normal-Tension Glaucoma

This other rare form of glaucoma is also known as low-tension or normal-pressure glaucoma. As the name implies, normal-tension glaucoma does not involve an increase in pressure inside the eye like with other forms of glaucoma. Instead, damage to the optic nerve occurs despite eye pressure being in the “normal” range of approximately 10-21 mm Hg.

The causes of normal-tension glaucoma are still not fully understood, though one possibility is that people with low-tension glaucoma simply have an abnormally sensitive optic nerve. Another theory is that they have a reduced blood supply to the optic nerve, for which there are multiple potential causes. 

Research has shown that those at higher risk for this form of glaucoma are:

• people with a family history of normal-tension glaucoma
• people of Japanese ancestry
• people with a history of systemic heart disease such as irregular heart rhythm.

Because there is much we still do not know about this form of the disease, normal-tension glaucoma is usually treated by attempting to lower intra-ocular pressure as low as possible. This is normally accomplished by medicine, laser treatment, traditional surgery or any combination thereof.

Secondary Glaucoma

Secondary glaucoma is any form of open-angle or angle-closure glaucoma which is caused by another disease or injury. Forms of secondary glaucoma include:

• Exfoliative Glaucoma, or pseudoexfoliative glaucoma, is caused when a flaky, dandruff-like material peels off the outer layer of the lens within the eye and collects in the angle between the cornea and iris.

• Neovascular Glaucoma is always associated with other abnormalities, most often diabetes. It is caused by the abnormal formation of new blood vessels on the iris and over the eye’s drainage channels.

• Pigmentary Glaucoma develops when pigment granules break off the iris (the colored part of the eye) and collect in the eye’s drainage structure. This is often preceded by a condition called pigment dispersion syndrome.

• Traumatic Glaucoma is the immediate or delayed development of open-angle glaucoma as a result of a blunt or penetrating eye injury.

• Uveitic Glaucoma develops as a result of inflammation of the uvea, the middle layer of the eye. This swelling can be caused by the inflammatory process itself or the medication (steroids) used to treat it. 

• Congenital Glaucoma occurs in infants whose eyes did not correctly or completely develop drainage canals. This rare condition, when uncomplicated, can often be corrected with microsurgery.

While anybody can develop glaucoma, research has shown that certain groups are at higher risk than others:

• African Americans over the age of 40 are six to eight times more likely to develop glaucoma than Caucasians.

• People Over 60, especially Hispanics/Latinos, are much more likely to get glaucoma than younger people.

• Those with a family history of glaucoma are at a much higher risk than the rest of the population. The most common type of glaucoma, primary open-angle glaucoma, is hereditary. Family history increases the risk of glaucoma four to nine times.

• Asians have an increased risk for angle-closure glaucoma.

• People of Japanese descent are at higher risk for normal-tension glaucoma.

• Users of steroids, such as those found in high-potency asthma inhalers, may have an increased risk of glaucoma.

• Eye injuries that bruise or penetrate the eye can cause traumatic glaucoma, either immediately or years later. Most eye injuries are related to sports, such as baseball or boxing.

• Other possible risk factors include:

• High myopia (nearsightedness)

• Hypertension

• Central corneal thickness less than .5 mm.

There is no permanent cure for glaucoma. Most individuals afflicted by this disease will need ongoing treatment and monitoring for the rest of their lives. Because glaucoma can progress and change without warning, having regular eye exams and adhering closely to a treatment plan is critical.

Even as new medications and treatments are being developed, early detection and prompt treatment remain the most important factors in successfully controlling glaucoma and reducing the chances of vision loss. While the American Optometric Association recommends that every adult have a comprehensive eye exam at least every two years, people at higher risk of developing glaucoma are encouraged to get a dilated eye exam annually. To schedule a comprehensive eye exam, request an appointment with Advanced Center for Eyecare here.