Glaucoma is a disease of the optic nerve, the part of the eye that carries images
we see to the brain.
The front of the eye is filled with a fluid, called aqueous humor. This fluid is
mostly water, and the main purpose is to inflate and maintain the shape of the eye.
This fluid is very similar to water in a balloon, and sometimes the eye pressure
can be too high. In such cases, pressure is placed on the optic nerve. This elevated
pressure causes damage to the optic nerve. If the optic nerve is damaged, then vision
cannot be transmitted from the eye to the brain, resulting in blindness. Unfortunately,
damage to the optic nerve is not typically reversible. Once vision is lost, it cannot
be restored. Therefore, screening and prevention are the keys to good glaucoma care.
If detected, glaucoma is often treated with topical medications (eye drops), laser
treatments or surgery.
There are many forms of glaucoma, but the hallmarks of all forms of glaucoma are
damage to the optic nerve and visual field loss. New risk factors for glaucoma are
always being discovered, but elevated intraocular pressure, increasing age, African-Americans
and a family history of glaucoma remain among the highest risk factors.
Common types of glaucoma include:
Primary open angle glaucoma (POAG) - Open angle glaucoma is the
most common form of glaucoma. It is generally painless and slowly progressive. It
is thought to be caused by changes in the drainage tissues of the eye. Although
this type of glaucoma usually involves both eyes, it can be asymmetric in severity.
Angle closure glaucoma - More frequent in women, angle closure
glaucoma is caused by anatomical changes in the relationship between the drainage
system of the eye (the angle), iris and lens. The normal drainage outflow becomes
blocked and the eye pressure elevates. This form of glaucoma can occur rapidly and
can be painful. It is frequently treated with a laser. The laser opens a hole in
the iris, restoring a more normal ocular anatomy and aqueous flow.
Pigmentary glaucoma - This type of glaucoma is seen when pigment
from the back of the iris deposits in the drainage tissues of the eye. This pigment
causes a blockage and elevated eye pressure. It occurs more frequently in myopic
Pseudoexfoliation glaucoma - A particular material, thought to
be from the lens of the eye, deposits in the drainage tissues and results in glaucoma.
Low tension glaucoma (LTG) - Low tension or normal tension glaucoma
presents as progressive visual field loss and optic nerve damage. However, the intraocular
pressure generally remains within a normal range.
Evaluation and Diagnosis
Screening for glaucoma can be done during a routine eye exam. The intraocular pressure
is measured and a slit-lamp exam is performed, which is a microscopic exam of the
anterior aspect of the eye. In addition, the optic nerve is examined for any evidence
of abnormalities (cupping).
If the examination is suspicious for glaucoma, more specific studies can be done.
These include visual field testing, optic nerve photography, and OCT (optical coherence
tomography). These studies may not only help make the diagnosis of glaucoma, but
help establish a baseline. Glaucoma in its most common form is a slowly progressive
disease. Therefore, establishing a baseline helps assess the rate of disease progression
and aid in the selection of treatment options.
Treatment options for glaucoma vary widely, depending on the form and severity of
glaucoma. Typically, for the most common form of glaucoma (open angle glaucoma),
treatment options will include medications, laser treatments, or eye surgery. Frequently,
a combination of these options may be used. The goal of glaucoma treatment is to
decrease intraocular pressure and prevent damage to the optic nerve. At the beginning
of treatment, the doctor will generally recommend medication or a combination of
eye drops and oral medications for the specific condition.
Glaucoma is a chronic condition that is not "cured" by the treatment; it requires
continued monitoring. When deciding on which treatment options, it is necessary
for the physician and patient to thoroughly discuss the risks and benefits.
Several different classes of glaucoma medications are available, including beta
blockers, prostaglandin analogues, alpha adrenergic agonists, miotics, oral and
topical carbonic anhydrase inhibitors, and rho kinase inhibitors. These medications
work by either reducing the rate at which fluid in the eye is produced or increasing
the outflow of fluid from the eye.
Laser treatment can improve drainage of eye fluid and reduce intraocular pressure. Although
surgery can be done to create a new passage for fluid drainage, it is usually reserved
for cases that cannot be controlled by medication or if laser treatment was not
Eye Drops - All eye drops may cause a burning or stinging sensation
at first. This is often due to the antibacterial agent present in the drop solution,
not the drug itself. While uncomfortable, it only lasts for a few seconds. It is
important that you take your medication exactly as prescribed.
Since eye drops are absorbed into the bloodstream, it is important that you tell
your doctor about all other medications you are taking. Some drugs can be dangerous
when mixed with others. Ask your doctor or pharmacist if the medications you are
taking together are safe. To minimize absorption into the bloodstream and maximize
the amount of drug absorbed into the eye, close your eyes for one to two minutes
after administering your drops and press lightly against the nasal corner of your
eyelids to close the tear duct that drains into the nose.
Oral Medications - Sometimes, drops are not enough to control intraocular
pressure. When this is the case, pills may also be prescribed. These pills also
serve to lessen the production of fluid in the eye. The medication is usually taken
two to four times daily. It is important to share this information with your other
doctors so that they can best prescribe medications for you that will not cause
potentially dangerous interactions.
Laser surgery has become increasingly popular as an intermediate step between drugs
and traditional surgery. The most common type performed for open-angle glaucoma
is called trabeculoplasty. This procedure takes 10 to 20 minutes, is painless and
can be performed in either a doctor's office or outpatient facility. The laser beam
is focused upon the eye's drainage area. Contrary to what most people think, the
laser does not burn a hole through the eye. Instead, its short bursts of energy
stimulate the drain to work better.
You may go home and resume normal activities following laser surgery. Your doctor should
check your intraocular pressure up to an later. After this procedure, nearly
75 percent of all patients respond well enough to be able to delay or even avoid
traditional surgery. It may take a few weeks to see the full pressure-lowering effect
of this procedure, during which time you may have to continue taking your medication.
Some patients are eventually able to discontinue some of their medications, however
this is not true in all cases. Your doctor is the best judge of determining whether
or not medication is still necessary for you. Cataracts do not occur after laser
surgery and complications are minimal, which are other reasons why this is a good option.
For persons with mild or moderate vision loss from glaucoma, newer minimally invasive
glaucoma surgeries may be another option. Variations of these procedures generally
involve enhancing drainage by bypassing the part of the drains that is clogged,
either with or without a special micro device.
The most common form of traditional surgery is called a trabeculectomy. It is typically
performed for moderate-to-severe cases of glaucoma. In this procedure, the surgeon
creates a small trap door in the eye wall to allow the aqueous humor to drain more
easily, reducing pressure in the eye. This procedure is usually done under local
anesthesia, as an outpatient procedure. It is important to note that your eyes may
not have their normal visual acuity for several weeks following this procedure.
Although trabeculectomy is a relatively safe surgical procedure, about one-third
of patients develop cataracts within five years of surgery. After trabeculectomy,
most patients are able to discontinue all anti-glaucoma medications. Ten to 15 percent
of patients require additional surgery.
Frequently Asked Questions
Is blindness caused by glaucoma preventable?
Regular diagnostic examinations by an ophthalmologist are important to preventing
loss of vision. Ophthalmologists are medical doctors who specialize in eye care
and trained to examine and treat eye diseases. Although there is no way to reverse
damage, if glaucoma is diagnosed and treated early, blindness almost always is preventable.
What are the symptoms of glaucoma?
Glaucoma is called the silent thief of sight. In most cases, glaucoma has no symptoms.
By the time an individual experiences decreased vision, the disease is frequently
in its later stages. Since early warning signs of glaucoma are rare, it is important
to have regular medical eye exams especially for those at risk.
Patients who may be at risk for glaucoma include:
- Those over 60 (in African-Americans, the risk is present at age 40 and older)
- A family history of glaucoma
- Race (African-Americans and Latinos are significantly more likely to get glaucoma)
- Certain medical conditions (diabetes, high blood pressure, heart disease)
- Physical injuries of the eye.
The symptoms depend on the type of glaucoma the individual has. Those who have chronic
glaucoma may not be aware of any symptoms because the disease develops slowly and
patients rarely notice loss of peripheral vision. Those who have an acute form of
glaucoma may develop severe symptoms because ocular pressure rises quickly. They
may experience blurred vision, especially at night, halos or rainbows around lights,
severe headaches or eye pain and nausea.
Is glaucoma painful?
Generally, the answer is no. In some forms of glaucoma, the pressure may become
extremely elevated (above 40 mm high). In such cases the patient may experience
pain, blurry vision, halos, or nausea and vomiting
Is there a cure for open angle glaucoma?
Unfortunately, there is no cure for glaucoma. Open angle glaucoma represents the
vast majority of glaucoma that affects patients in the United States. However, there
are treatments that can reduce or even halt the progression of the disease. These
treatments include topical medications, laser surgery, and surgery to increase the
rate of fluid drainage from the eye. Which treatment is best depends on the individual
patient, as well as the type and severity of their glaucoma.
If I think the medication I'm using is causing side effects, should I stop using
it for a while to see if there is an improvement? What medication should be used
to treat the glaucoma during this time?
Most patients can safely suspend a medication suspected of producing unpleasant
side effects for approximately one to two weeks. Your ophthalmologist may suggest
that you return sooner based upon the amount of damage to your optic nerve and the
level of your intraocular pressure. Depending upon the particular class of medication,
it may take one to four weeks to be completely rid of the drug's effect.
What are some of the side effects of using latanoprost, travoprost, or bimatoprost?
The most common side effects of latanoprost (Xalatan) and the other medications
in its class are stinging and burning related to corneal irritation, conjunctival
injection (redness) and, in some patients, a darkening of the iris color. Your complaints
may represent either a side effect or allergic reaction to this medication. Both
of these are unlikely to disappear on their own. Latanoprost allergy or intolerance
is not uncommon and may occur in as many as 5 percent of patients who are currently
using other classes of antiglaucomatous medication. As always, call your doctor
if you have an adverse reaction to any medication.
What are the most common side effects of eye drops used to control glaucoma?
All medications can have side effects, though not all medications cause side effects
in all people. If you have side effects with one medication, it makes sense to try
a different one. There are a number of different classes of medications available
for treatment of glaucoma. The only way to tell if a medication is causing side
effects is to stop the medication and see if they go away, then start the medication
again to see if the side effects return, then repeat this process once again. Sometimes,
it is the preservative in the medications rather than the medications themselves
that cause the side effects. In such cases, it is possible to get preservative-free
What's the best treatment for glaucoma: surgery or medication?
Quality of life is an important factor in the treatment of any chronic ailment.
It is important to make a decision as to whether you want to live with significant
side effects. You should first consider whether there is a way to eliminate the
side effects of the medications you are taking. Talking with your ophthalmologist
is the best approach to identifying possible ways to resolve the problem of medication
If you are still suffering from intolerable side effects, or if your glaucoma is
uncontrolled, then surgery may be an option.
Glaucoma surgery is safer and more effective than ever. Surgery for
uncomplicated open-angle glaucoma, when performed as an initial surgical procedure
in a patient who has not had previous intraocular surgery, is highly effective.
The chance of complications or surgical failure increases with previous intraocular
surgery, complicated glaucoma, having to redo the operation for glaucoma and severe
Why do some people with glaucoma and high pressure respond to as little as one
eye drop while another person with a lower pressure needs to take three or four
The extent or seriousness of glaucoma damage to the eye cannot not be judged by
the intraocular pressure alone or the number of glaucoma medications required to
control it, but rather should be defined by the amount of damage to the optic nerve
and visual field. This is an important point. Glaucoma is a disease characterized
by progressive injury to the nerve; this results in loss of vision that can be detected
on a visual field test.
The response to glaucoma medications varies among individuals. Some individuals
respond nicely to a single agent; others may require multiple medications to control
their disease and prevent further vision damage. The desired intraocular pressure
is chosen by the treating physician and based upon the extent of the glaucoma damage,
the intraocular pressure at which the damage occurred and other factors.