Dr. John B. Cox and Dr. Heather Estopinal

Glaucoma: The Basics

Glaucoma is a disease of the optic nerve, which transmits the images you see from the eye to the brain. The optic nerve is made up of many nerve fibers (like an electric cable with its numerous wires). Glaucoma damages nerve fibers, which can cause blind spots and vision loss.

Glaucoma has to do with the pressure inside the eye, known as intraocular pressure (IOP). When the aqueous humor (a clear liquid that normally flows in and out of the eye) cannot drain properly, pressure builds up in the eye. The resulting increase in IOP can damage the optic nerve and lead to vision loss.

Your ophthalmologist may tell you that you are at risk for glaucoma if you have one or more risk factors, including having an elevated IOP, a family history of glaucoma, certain optic nerve conditions, are of a particular ethnic background, or are of advanced age. Regular examinations with your ophthalmologist are important if you are at risk for this condition.

The goal of glaucoma treatment is to lower your eye pressure to prevent or slow further vision loss. Your ophthalmologist will recommend treatment if the risk of vision loss is high. Treatment often consists of eye drops but can include laser treatment or surgery to create a new drain in the eye. Glaucoma is a chronic disease that can be controlled but not cured. Ongoing monitoring (every three to six months) is needed to watch for changes. Ask your ophthalmologist if you have any questions about glaucoma or your treatment.

Ocular Hypertension

If the doctor diagnoses you with “ocular hypertension” he is saying that the pressure in the eye is running on the high end of normal, or above 21. Elevated pressure can damage the sensitive visual structure in the back of the eye.  When pressure causes damage it becomes glaucoma and must be treated.  It is very important to be examined regularly if you have ocular hypertension.  During your appointment, the doctor will examine the eye for changes in the visual system and if needed can begin therapy to control the intraocular pressure and make every effort to prevent vision loss.

REMEMBER, OCULAR HYPERTENSION CAN LEAD TO GLAUCOMA.  GLAUCOMA CAN CAUSE LOSS OF SIDE VISION THAT IS NOT NOTICEABLE IN THE EARLY STAGES AND POSSIBLE TOTAL BLINDNES THAT CANNOT BE REGAINED. DON’T MISS THAT APPOINTMENT!!

Primary Open-Angle Glaucoma

The most common form of glaucoma is primary open-angle glaucoma, in which the aqueous fluid is blocked from flowing back out of the eye at a normal rate through a tiny drainage system. Most people who develop primary open-angle glaucoma notice no symptoms until their vision is impaired.

Normal Tension Glaucoma

Even some people with “normal” IOP can experience vision loss from glaucoma. This condition is called normal-tension glaucoma. In this type of glaucoma, the optic nerve is damaged even though the IOP is considered normal. Normal-tension glaucoma is not well understood, but lowering IOP has been shown to slow progression of this form of glaucoma.

Narrow Angle Glaucoma

In narrow angle glaucoma, the drainage system of the eye gets progressively smaller.  This may worsen with the development of cataracts and is more common in hyperopic (far sighted) patients.  Patients with narrow angles may have sub-acute attacks of angle closure when the eye becomes mid-dilated.  This may happen after sitting in a dark room (ex. in a movie theater).  The eye may ache, become red, and the vision may be slightly blurred.  If you experience these symptoms, you should call and let your ophthalmologist know.  Anti-histamine medications may worsen or precipitate these events.  If you think you may be having these symptoms, do not take any anti-histamine type medication until it is approved by your doctor.  In some cases, the angle may appear shallow, but may not be narrow enough to warrant surgical intervention.  In these cases, the doctor will closely monitor the angle structure and will ask you to notify him of any symptoms.  If the angle should become narrow enough to be at risk for closure, an iridotomy may be recommended.

In angle-closure glaucoma, the iris (the colored part of the eye) may drop over and completely close off the drainage angle, abruptly blocking the flow of aqueous fluid and leading to increased IOP or optic nerve damage. In acute angle-closure glaucoma there is a sudden increase in IOP due to the buildup of aqueous fluid. This condition is considered an emergency because optic nerve damage and vision loss can occur within hours of the problem. Symptoms can include nausea, vomiting, seeing halos around lights, and eye pain.

Traumatic Glaucoma and Hyphema

If your eye is injured, there is a chance you will develop traumatic glaucoma. A direct blow to the eye can cause bleeding or inflammation in the eye, which may lead to an acute rise in eye pressure. This condition can typically be managed with eye drop medication. However, if the intraocular pressure (IOP) is very high or if blood remains in the eye, surgical treatment may be required.

If an eye is hit hard enough to cause bleeding in the front part of the eye, this is called a hyphema. A hyphema increases the possibility of a rise in IOP. Various medications can bring the pressure down to a safe zone until the blood decreases or disappears.

In cases of a hyphema, there is also a chance of a future increase in IOP. The chance of developing elevated IOP and glaucoma following a hyphema is thought to be approximately 8% over a patient’s lifetime. Therefore, anyone who has had eye trauma should be sure to have intraocular pressure checks every year. If your ophthalmologist (Eye M.D.) notes an increase in your eye pressure, he or she can find ways to control it.

Pigmentary Glaucoma

Pigmentary dispersion syndrome is a condition in which increased amounts of pigment circulate within the front portion of the eye. This often results in having pigment layered on the back of the cornea, thinning of the iris, and clogging of the ocular drainage system with pigment. This pigment can block the drainage channel enough to cause an increase in intraocular pressure (IOP).

In cases of pigmentary glaucoma, the IOP often is very high, reaching levels above 40 mm Hg. Pigmentary dispersion leads to damage from glaucoma in 20% to 50% of patients. It is more common in males and often appears in people under 50 years of age.

Treatment is the same as for other forms of open-angle glaucoma, including medications, laser therapy, or surgery. With adequate treatment, the prognosis for pigmentary glaucoma is good.

Childhood Glaucoma

Childhood glaucoma, which starts in infancy, childhood, or adolescence, is rare. Like primary open-angle glaucoma, there are few, if any, symptoms in the early stage. Blindness can result if it is left untreated. Like most types of glaucoma, childhood glaucoma may run in families. Signs of this disease include:

• clouding of the cornea (the clear front part of the eye)
• tearing
• enlarged eye