Glaucoma

The M.D.s at Sierra Eye Associates provide comprehensive eye exams include glaucoma evaluations.  We are proud to have the only fellowship trained Glaucoma Subspecialist in Northern Nevada in Michael L. Stanko, M.D.

Glaucoma: Prevent the Loss with Early Diagnosis

Glaucoma is a disease of the optic nerve, and is a very common cause of blindness in older individuals, though it may begin at a young or middle age. The optic nerve is located at the back of the eye and connects the eye to the brain. When the nerve is damaged by glaucoma, there is a gradual loss of side vision, the “visual field.” Late in the disease, center vision can also be lost, which can cause blindness if the glaucoma is detected too late. Glaucoma has no symptoms. Fifty percent of those who have glaucoma are not aware of it. If glaucoma is detected early, most patients will not go blind. African-Americans may be at least four to five times more likely than white patients to develop glaucoma.

 

Risks of Glaucoma

The Baltimore Eye Survey examined all willing residents of a region in East Baltimore for any type of eye disease, with half of those with glaucoma not knowing they had it. This study ran through Johns Hopkins University. The rate of glaucoma was similar for men and women. In those over 40 years old, glaucoma was found overall in 5% of African-Americans and less than 1% of whites. Glaucoma becomes more common with increasing age. The rate of glaucoma above age 80 rose to nearly 3% in whites, but in African-Americans rose progressively up to over 11% above age 80, and this percentage was even higher if “glaucoma suspects” were included. A “glaucoma suspect” is a person whose optic nerve looks as if it may have glaucoma, but this cannot be proven.

 

Family History

Glaucoma may run in families. Ask if anyone in your family takes eyes drops on a regular basis or has a history of blindness. Close family members of a person with glaucoma should be checked for glaucoma. The highest risk is having a close blood relative who lost vision from glaucoma or who has required glaucoma surgery. This may even have a stronger relationship in African-Americans, in whom glaucoma may start at a younger age and be more aggressive. The best way to prevent vision loss is to begin regular eye exams early. It is never too early to begin regular eye exams. It may be wise to be sure you have regular exams, especially if there is a family history of glaucoma.

Glaucoma is a slowly progressive disease; patients do not usually notice any signs or symptoms of the disease until their vision is already affected. The only way for a person to know if they have glaucoma is through regular, complete eye exams, where the pupils get dilated, or enlarged temporarily with eye drops, to examine the optic nerve in detail. Wearing glasses has nothing to do with glaucoma. Patients who wear glasses may be more likely to have their glaucoma detected only because they have had their eyes examined.

 

Diagnosis of Glaucoma

A diagnosis of glaucoma is based on the appearance of the optic nerve. Elevated eye pressure was typically associated with glaucoma, but blood flow problems to the optic nerve may also be part of the cause. The normal eye pressure used to be considered 10-21 mm Hg. However, up to one third of all glaucoma patients may never have an eye pressure over 21 mm Hg. Eye pressure can vary quite a bit in glaucoma. While elevated eye pressure is common, patients can have high eye pressure without glaucoma, or may have damage from glaucoma with normal levels of eye pressure. Persons who have ever been told they had high eye pressure should be sure to have a complete eye exam and begin regularly scheduled exams in the future.

During the eye exam, the vision is tested, the eye pressure is measured, the internal drainage system of the eye is evaluated, and the front and back of the eye are thoroughly examined. A visual field test may also be performed. This is a standardized computer test of the side vision, or visual field. However, visual field loss may not show up early in the disease. Photographs of the optic nerve may be taken, which serve as a comparison to determine if there are changes in the future.

 

Types of Glaucoma

The most common type of glaucoma is chronic open-angle glaucoma. This is the type of glaucoma in which the drainage channel of the eye does not function properly and slow damage to the optic nerve occurs. Acute angle-closure glaucoma is much less common and occurs when the drainage angle suddenly closes off. This results in a sudden rise of pressure and it requires immediate attention. A person at risk for this can often be treated by a laser procedure which can prevent the sudden increase in eye pressure; this can be detected by looking for a particular shape of the drainage channel, called a “narrow angle.” Normal tension glaucoma occurs when an individual suffers optic nerve damage secondary to pressure in their eye which is within the normal range; scientists believe these patients may have a genetic predisposition to optic nerve damage. “Secondary” glaucoma usually results from a preexisting eye or medical problem, such as diabetes, trauma, blocked blood vessels, or inflammation.


In a “normal” eye, fluid production and drainage from the eye is equal. No excess pressure builds up within the eye. In normal tension glaucoma, optic nerve damage occurs at normal eye pressures.

In open angle glaucoma, usually there is too much fluid production for the drain to handle, resulting in increasing pressure within the eye.

Angle closure glaucoma involves continued fluid production without adequate drainage, also resulting in increasing pressure within the eye.

Diabetes may be associated with glaucoma, although the relationship is unclear. Persons with diabetes should have their eyes checked regularly as this is also a major cause of blindness.

Treatment of Glaucoma

While not all patients with glaucoma have high eye pressure, the eye pressure is all that is currently available to treat, and a “target” pressure level is set for each patient where the patient should not have further damage. There are different types of treatments available for lowering the eye pressure. These include eye drops, laser, or surgery. The treatment is chosen as to what is most appropriate for an individual patient; not all patients receive the same treatment. To begin treatment, patients most commonly receive eye drops, and may require only one type or several types of drops used together to reduce the eye pressure. Laser to the drainage system has also recently become accepted as a beginning treatment; this is decided with the patient on an individual basis. Surgery is used when medications and laser have failed, but there is current research to see if surgery earlier is better for the patient. The surgery, called a trabeculectomy, creates a new passage for fluid to drain out of the eye. This surgery may also be done in combination with cataract surgery when appropriate.

Glaucoma is not presently curable, but is treatable. Early diagnosis by regular eye examinations, close follow-up, and compliance with treatment are the best methods to prevent vision loss. Many medications are available for treatment, and new research is continually being done to develop new ways to treat or prevent glaucoma.

Please call (775) 329-0286 if you would like to schedule an appointment.