What You Should Know About Glaucoma

What is glaucoma?
Glaucoma is a complex disease associated with the build-up of fluid pressure inside the eye which, left untreated, can damage the optic nerve.  The optic nerve, a bundle of more than a million nerve fibers, transmits the message of sight from the eye to the brain. The nerve fibers carrying peripheral vision are normally lost first. This reduction in side vision can be gradual and is not usually noticed. By the time it affects central or reading vision, tremendous damage to the nerve has occurred.  

Normal Vision.		Glaucoma.

To understand what’s happening with glaucoma, imagine the eye as a bathtub with water. The clear fluid inside the eye, the aqueous humor, is always flowing through the eye, just like an open faucet. As long as the drain is open, the tub won’t overflow. But if anything happens to block the drain, the water level rises and spills over the edge.

Any blockage in the drainage system of the eye (trabecular meshwork) creates a similar problem, but the fluid has nowhere to overflow. Rather, the fluid pressure increases and damages one of the most sensitive, and important, parts of the eye, the optic nerve. Treatment, usually with simple eye drops, can prevent further loss of vision but cannot restore what has already been lost; therefore, early detection is essential.

Is there more than one type of glaucoma?
Although there are many different causes of glaucoma, there are two broad categories, open angle glaucoma and narrow angle glaucoma. The most common form is chronic open angle glaucoma. In this condition, a partial blockage in the drainage system of the eye causes the pressure to gradually increase inside the eye, just as though you were standing in your shower and noticed the water rising. You look down at the drain and see nothing is blocking it. The clog is somewhere deep inside the drain. This form of glaucoma usually causes no pain or sensation. The vision is lost slowly, starting in the periphery so that it is generally not noticed until significant damage has occurred, unless it is detected earlier by your eye specialist.

The various types of glaucoma are usually categorized by where the blockage affects the outflow drainage area.		The iris blocks the drainage area in narrow angle glaucoma (above). The drainage system within the eye wall is primarily affected in open angle glaucoma (below).

 
The other major form of glaucoma is narrow angle glaucoma, also known as angle-closure glaucoma. This form of glaucoma can again be likened to your standing in the shower and noticing the water filling up in the tub. As you look down, you notice that your foot is covering the drain. The iris, the colored part of the eye, has moved forward, blocking the openings into the drainage system, causing a sudden rise in the pressure in the eye. This can result in halos around lights, severe pain and rapid loss of vision.

Both of these types of glaucoma can be inherited. Therefore, if someone in your family has glaucoma, your risk of developing glaucoma is increased.  Likewise, if you have glaucoma, others in your family need to be made aware that their risk is heightened.

How is glaucoma diagnosed?
At Bennett & Bloom Eye Centers, our doctors use the very latest technology to identify patients with glaucoma. The diagnosis of glaucoma is not always clear-cut and simple, since individuals vary in their susceptibility to eye pressure. Successful diagnosis and treatment of glaucoma begins with a careful ocular evaluation. First, we measure the fluid pressure within the eye. Corneal thickness may affect this pressure reading and can be checked with an ultrasonic pachymeter. We examine your eyes thoroughly and look for optic nerve damage, both visually and photographically. Using the state-of-the-art GDx® Nerve Fiber Analyzer, we can measure the nerve fiber layer thickness around your optic nerve. This test may determine if you have glaucoma even before you experience any vision loss. Next we test for central and peripheral vision loss using a sophisticated, computerized visual field analyzer. Gonioscopy helps determine which specific type of glaucoma you may have.

We’re always careful to consider any additional risk factors that may contribute to your possibility of vision loss from glaucoma. Family history, general health problems, including diabetes and anemia, as well as prior eye trauma and race are all risk factors.

Finally, we analyze all the information to arrive at your diagnosis and then decide on a treatment plan if indicated. Special eye drops, usually taken once or twice a day, are all that is needed to stop sudden damage or loss of sight.

How is glaucoma treated?
1) Open angle glaucoma in most cases, can be treated with topical eye drops. These drops help lower the intraocular pressure and reduce the risk of vision loss from glaucoma. Sometimes more than one drop is needed.  If these drops do not adequately control the pressure, there are surgical options that can be performed as the next step in lowering the eye pressure. Some patients are able to decrease the number of eye drops they use (and in some cases, eliminate them completely) after surgery.  However, it is important to realize that this is not always the case, and drops may still be necessary in addition to surgery to keep the pressure at a safe level.

• Argon Laser Trabeculoplasty (ALT)
  An argon laser can be  used to widen the openings in the drainage system, thereby lowering the pressure. This medical laser treatment is normally safe, painless, quick and is performed in our office.
  
  
• Selective Laser Trabeculoplasty (SLT)
  SLT can be used to widen the openings in the eye's drainage system, thereby lowering the pressure. This medical laser treatment is normally safe, painless, quick and is performed in our office.
  
  Compared to traditional argon laser trabeculoplasty, selective laser trabeculoplasty does not burn trabecular meshwork tissues. SLT uses an extremely short burst of laser energy to selectively treat pigmented cells found in the trabecular meshwork. Pigment cells that may be clogging the trabecular meshwork are removed without causing any structural changes or scarring to the trabecular meshwork. This fact offers a distinct advantage over ALT in that SLT may potentially be repeated as needed by the patient. Lowering intraocular pressure by SLT may also reduce the need for patients to use eye drop medications. Eye drops have obvious disadvantages of expense; potential side effects and they require a lifetime of compliance. SLT is also a patient friendly procedure. It can be performed in the office in about 5 minutes with only topical anesthesia. Patients who are not controlled by eye drops, who cannot afford eye drops or who have poor compliance with eye drops are good candidates for SLT.
  
  
• Ex-PRESS™ Mini Glaucoma Shunt
  Rarely, in cases in which traditional medical and surgical techniques are not working, the Ex-PRESS™ Mini Glaucoma Shunt can also be used. This is a minimally invasive procedure compared to some other surgical alternatives for glaucoma. It involves the implantation of a miniature device that reduces pressure inside the eye by diverting the excess fluid away from the affected area.
   
  The potential of trauma to the delicate eye tissue is greatly decreased. The procedure allows for a very small incision to be made, using a specially designed disposable insertion tool. The actual device is a 400-micron diameter tube less than 3 mm long, made from an implantable stainless steel. The surgery also does not require removal of any portion of the iris (iridectomy) as is required with conventional glaucoma filtering surgeries.
  
  
  
  
  The use of only eye drops for anesthesia combined with the minimal invasiveness, allows the procedure to be completed in a fraction of the time of conventional glaucoma filtering surgery. Clinical studies have shown the procedure produces low complication rates with fast recovery and minimal discomfort to the patient. Implantation of the device can reduce or eliminate the reliance on glaucoma medications. Specifically, the studies have found a 40% reduction in intraocular pressure with an 88% success rate.
  
  Drs. Donald Bennett and Steven Mattas were among the first physicians in the U.S. to be successfully certified to perform this procedure.
  
  
• Trabeculectomy
  The doctor surgically creates an incision in the drainage channel of the eye. This creates an artificial drainage channel, allowing the fluid to escape from the inner part of the eye, lowering the pressure. This procedure may be done alone, or in combination with cataract surgery if a visually significant cataract is present. There are no lasers used in this procedure. Some forms of glaucoma respond better to laser treatment, while others respond better to conventional surgery.
  

2) Narrow angle glaucoma is usually treated with a YAG laser iridotomy.  This laser is used to produce a small opening in the colored iris, allowing it to fall back away from the drainage area of the eye.  Again, this treatment is usually fast and safe and is done as an outpatient in our office. It should be noted that laser treatment may not be recommended for all types of glaucoma. Also, laser treatment attempts to preserve the vision that remains, not to restore the vision that has already been destroyed.

How do I put eye drops in my eye?
It is important to use drops correctly to get the proper dose into your eye.

1) Either lie down or lean your head back.

2) By pulling down the lower lid with the index and middle finger of one hand, a pocket is formed between the lid and your eye.

3) The other hand holds the bottle and is rested against the hand holding the eye open (for support). The tip of the bottle should be near the eye but not touching it. Just one drop is squeezed out and should fall through the air into the pocket.

4) Gently close your eyes for several minutes while firmly pressing the area between the corner of your eye and your nose with an index finger.

This last maneuver accomplishes two things. First, it helps keep the drop in contact with your eye longer, thus increasing its effect. Second, by blocking the tube which leads from the eyelid to the nose, it keeps the medication out of your nose, where it can be readily absorbed into the bloodstream and possibly cause some unwanted side effects. If you have questions regarding this technique, please ask us.

If more than one kind of eyedrop is being used, it is important to wait at least five minutes between the drops so as not to dilute them and decrease their effect.

It is important to remember that eye drops, like laser treatments for glaucoma, will not restore any vision already lost. Therefore, you will not see any better after starting the drops, but they will help to prevent further damage that could cause you to lose more vision if left untreated. The main goal of the drops is to lower the pressure in the eye to preserve the vision that has been unaffected by glaucoma.

Will I go blind from glaucoma?
Virtually no one should be blinded from glaucoma. The treatments are highly effective and, while vision already lost cannot be restored, significant further loss can be avoided.

The most important ingredient in the successful management of glaucoma is your cooperation. Continuous pressure control is possible only by strictly following your treatment plan…and that is primarily up to you.

In most cases, the only people who become blind from glaucoma are those who do so before their condition is diagnosed or those who do not adhere to their treatment regimen.

Will some medications worsen my glaucoma?
Many over-the-counter medications are labeled not to be used if you have glaucoma. These warnings do not apply to open angle glaucoma, but only to untreated narrow angle glaucoma.

A few reminders about glaucoma.
In most forms of the disease, glaucoma has little to no warning signs. It is impossible to "feel" a change in the eye pressure unless it becomes extremely high. Once the vision becomes so reduced that visual changes are noticed, damage to the optic nerve has already begun and cannot be reversed. The goal of treatment at that point is to preserve any remaining vision. This is why routine examinations and compliance with medications are so important. If detected early enough, there is an excellent chance of lowering the eye pressure and preventing sight threatening damage from occurring.

Even after undergoing a surgical or laser procedure, eye drops may still be needed in some cases to reduce the pressure to a safe range. It is also important to remember that certain types of glaucoma respond better to laser surgery, while others respond better to conventional surgery.

With eye drops, compliance is the key. Most people will probably not notice any difference in their vision after starting eye drops. The goal of eye drops is to lower eye pressure, prevent damage and further vision loss, not to improve the current vision. Therefore, even though patients may not feel any different or see better, it is important to continue to use the prescribed medication. By measuring the pressure at follow up visits, your doctor will be able to tell you if the treatments are effective.