Barnet Dulaney Perkins Eye Center Official Blog

Lasers have become a critical tool in treating and preventing many types of glaucoma.  Lasers were first used in treating glaucoma less than 35 years ago.  Prior to their introduction, glaucoma could only be treated medicines or surgery.  Lasers now serve as an intermediate treatment between medicine and surgery. Patients are often intimidated by the thought of having to undergo laser treatment. However, those patients who have undergone successful laser treatment will most likely tell you that their experience was pleasant, painless, and fast.  Most laser treatments used in the management of glaucoma are performed in an office setting.  Lasers usually do not involve needles, sutures, cutting, or bleeding.

There are several types of laser procedures used in the treatment of glaucoma.  The most important aspect of laser use in the management of glaucoma is understanding who is a candidate.  It is also important that the patient have realistic expectations about what lasers can achieve. In general, lasers do not “cure” glaucoma.  Rather, they serve as an important “treatment” used to control this lifelong disease.

Historically, the primary treatment for glaucoma has been eye drop medications. When a patients’ glaucoma can no longer be controlled on eye drops alone, or if they cannot tolerate the eye, they are considered candidates for laser therapy.

An important concept to understand in glaucoma is that of a patient who is on a “Maximally tolerated medical regimen (MTMR.)  Many different scenarios can be considered MTMR. Here are a few examples.

1.   A patient who is on three or four eye drop medications but who still has a pressure that is higher than the target set by their eye doctor.
2.    A patient who is on one or two eye drop medications but who is intolerant to all other medications and who is running a pressure above the target set by their eye doctor
3.    A patient who has no problem tolerating eye drops, but who has severe arthritis or Parkinson’s disease.  This patients may have limited use of her hands and have difficulty putting in eye drops.  If this patient lives alone, and has no one to rely on to instill her drops, she would be considered MTMR

Thus, you can see from these examples, that laser treatment may become necessary at different stages for different patients.  There is no question that eye drop medications should be tried as initial therapy.  If medical therapy is ineffective, the patient becomes a candidate for laser therapy.

Laser therapy is an effective way to lower pressure.  Laser therapy is used to complement the effect of eye drop medications.  Laser therapy does NOT replace eye drops medications in most instances.  Instead, laser is used to augment the effect of the existing medications.  It should be carefully explained to patients that they may still need to use glaucoma medications following successful laser therapy.
Laser therapy does not provide permanent pressure reduction. The benefits of laser can last anywhere from 6 months to 6 years.  Often the treatments can be repeated at least once.  There are a small percentage of patients in whom laser may not lower the eye pressure to a significant degree.

LASER SURGERY FOR GLAUCOMA

WHAT IS THE DOWNSIDE OF LASER THERAPY?

In most instances, the downside is very small.  I tell my patients that the worse thing that can happen is that they do not get any benefit from the treatment.  Because the procedure is non-invasive, patients are not exposed to the risk of severe bleeding or infection, which are notable risks with surgery.  A small percentage of patients may experience a transient rise in their eye pressure over the first 24 hours following the procedure, but this is short-lived.

Thus, I offer laser treatment to my patients as an option to help control their pressure and avoid surgery.  I also tell my patients that the benefits of most laser treatments are not forever, and that if they live long enough, they will likely need surgery in the future.

Laser therapy is an excellent bridge between medical and surgical management of glaucoma.  There is a limited downside, and a moderate but not permanent upside.

WHAT IS NEW IN LASER THERAPY?

There are at least two new lasers on the horizon for the treatment of glaucoma.  One laser called the “diode” laser is now in use in our practice. Within the next 12 to 24 months we will see the incorporation of a new type of laser for the treatment of glaucoma.  This new laser is called the Selecta 7000.  This laser is a breakthrough because it will allow us to perform laser treatment on patients who have already undergone “complete treatment” with our existing lasers.  Prior to the inception of the Selecta 7000, laser treatment was performed only twice. It was felt that additional treatment could do more harm than good.  With the Selecta 7000, we are achieving excellent results in treating people how have had “complete treatment” with our standard lasers.

WHAT TYPES OF LASER SURGERY ARE THERE FOR GLAUCOMA?

The most common procedures performed for glaucoma are:

1.    Laser trabeculoplasty
2.    Laser iridotomy

I will discuss the indications and procedures for both of these treatments.  Many patients may require both treatments over the course of their lives.  These treatments were introduced into ophthalmology nearly 30 years ago.  The main changes since their inception have been related to improved laser technology.  The fundamental principles and goals of these treatments remain unchanged.   The goals are to improve drainage of the fluid which fills the eye.

LASER SURGERY FOR GLAUCOMA-ARGON LASER TRABECULOPLASTY (ALT) &  DIODE LASER TRABECULOPLASTY (DLT)

Argon laser trabeculoplasty is a laser procedure, which is performed in an office setting.  The patient is seated in a comfortable position, and the eye numbed with eye drops.  The treatment takes less than 5 minutes to perform, and usually causes only mild pain.  Most patients tolerate the procedure without difficulty.  There is little to no discomfort following the procedure.

Argon laser trabeculoplasty (ALT) is an important adjunct to medical and surgical treatment of open-angle glaucoma.  Diode laser trabeculoplasty (DLT) is apparently equally effective.  The indications and techniques for performing ALT have become standardized since its introduction in 1979.

PATHOPHYSIOLOGY:

The mechanism by which ALT lowers eye pressure is not known, although an immediate “mechanical” effect on the trabecular meshwork (drain of the eye) is widely accepted.  Besides the immediate thermal effect of the burns on surrounding tissues, including tightening of the meshwork (circumferential shortening), there may be a long-term metabolic effect.

INDICATIONS:

ALT should be considered for patients with open-angle glaucoma who cannot be controlled by a maximum tolerated medical regimen (MTMR.)  Additionally, it should be considered in those patients who are intolerant to or unable to use topical medications.  ALT is also appropriate as a method of delaying filtering surgery, especially for the systemically fragile elderly patient.  A follow-up of patients enrolled in the Glaucoma Laser Trial (GLT) showed that initial treatment with ALT of newly diagnosed patients with open-angle glaucoma was at least as effective as initial treatment with eye drops.

ALT is relatively successful in patients over 50 years of age with primary open-angle glaucoma, especially in cases associated with pseudoexfoliation and pigmentary dispersion.  ALT has poor success in eyes with congenital or juvenile-onset glaucoma, inflammatory glaucoma, and post-traumatic glaucoma with angle recession injury.  The effects are relatively unpredictable in patients who have undergone prior cataract surgery.

EXPECTATIONS:

ALT produces an average decrease in eye pressure of  7 to 10mm Hg.  The amount of eye pressure drop obtained increases as baseline pressure increases.  Eye pressure tends to drift back toward the baseline following ALT.  The average benefit in eye pressure control lasts 2 to 5 years.  By 5 years after ALT, about 46% of treated patients remain better controlled.  The failure rate is approximately 10% per year and, by 10 years after ALT, one half of treated eyes have undergone filtering surgery.

SUMMARY:

ALT is a safe, widely performed procedure.  The following pages illustrate the treatment process.

LASER SURGERY FOR GLAUCOMA -LASER IRIDOTOMY

INDICATIONS:

Laser iridotomy is indicated in the treatment of acute and chronic angle-closure glaucoma, combined-mechanism glaucoma, pseudophakic and aphakic papillary-block glaucoma, and incomplete surgical iridectomy.

ANGLE CLOSURE GLAUCOMA:

Angle-closure glaucoma must be given a high priority among eye diseases because its effects can be devastating.  Bilateral blindness can result in 2 to 3 days from onset.  Angle-closure glaucoma, can be prevented with proper recognition and therapy.  Few conditions in ocular disease offer such a great opportunity for relief of human suffering.  There is a dramatic difference between the devastation of untreated angle-closure glaucoma and its permanent prevention with early recognition and appropriate treatment.

NARROW ANGLE GLAUCOMA:

Narrow angle glaucoma can and should be recognized by all eye care physicians.  The condition, if treated promptly with laser iridotomy, can greatly reduce the chances of visual impairment.  The INITIAL treatment for narrow angle glaucoma is laser iridotomy.  This procedure is done in an office setting, with the patient seated in a comfortable position.  The eye is numbed with anesthetic eye drops.  A special contact lens is placed on the eye, and the laser used to make a small hole in the colored part of the eye known as the iris.  This small hole is usually not detectable with the naked eye.  The hole is usually placed superiorly, in an area covered by the upper eyelid.  Narrow angle glaucoma can occur in people of ALL ages.  It is not uncommon to first diagnose this condition when patients are in their late 30’s or early 40’s.  Many patients when initially told that they have this condition become quite alarmed.  Their alarm grows when the doctor informs them that the initial treatment for this condition is laser surgery.  Patients often want to know if they can use eye drops instead of having laser surgery.  Unfortunately, this is one disease where eye drops CANNOT take the place of laser treatment.  Equally disappointing to the patient at first pass is the fact that some people will require drops even if laser surgery is successful.  Those patients have what is known as combined mechanism glaucoma.

Most important, however, is the fact that this is a treatable disease.  The laser treatment usually takes only a few minutes, but its benefits can last a lifetime.  .

If a patient has doubts about the diagnosis and the need for treatment, they should seek a qualified second opinion immediately.  This often allays their fears, and allows them to proceed with the procedure without hesitation.

GLAUCOMA SURGERY-LASER IRIDOTOMY

SURGICAL TECHNIQUE:

The patient is premedicated with a topical anesthetic.  Pretreating the patient with a miotic agent such as pilocarpine is advantageous.  The miotic pupil provides greater iris surface area for treatment, ensures a thinner iris for easier penetration, and minimizes the chance of errant laser energy causing retinal injury.  Pre-treatment with medications which lower eye pressure is recommended, because 30% of patients develop elevated pressure after laser iridotomy.  Pretreatment with alpha-adrenergic agents such as apraclonidine (Iopidine,) or Brimonidine (Alphagan,) may prevent a post laser spike in IOP.  These topical medications also may limit the amount of iris bleeding when the Nd:YAG laser is used.  In addition to these medications being given 1 hour before the laser surgery, a second drop is applied at the completion of the treatment.

RESULTS:

The end point of treatment for both laser modalities (Argon, YAG) is a well-defined, clean, hole.

POSTOPERATIVE CARE:

After treatment, the patient should be examined during the subsequent 1 to 3 hours and again within the next week.  Patients should be given topical steroids to be used hourly on the day of the procedure, then q.i.d. for 4 more days.

The following page demonstrates the type of iris burn attained with the two types of lasers used to create the iridotomy.  The procedure can be performed using either one or two lasers.  Some patients are treated using only one laser, while other patients require the use of two lasers. The decision of using one or two lasers is made by the surgeon.  This decision is based upon the unique anatomy of each individual’s eye.

Glaucoma is a treatable disease. Glaucoma, however, has no cure. Glaucoma is defined by optic nerve damage. In a majority of cases, glaucomatous optic nerve damage is caused by elevated intraocular pressure (pressure within the eye.) It is important to note, however, that nearly 25% of individuals with glaucoma do not demonstrate elevated pressures over the course of their lifetime.

The systemic disease which glaucoma most closely resembles is “high blood pressure (systemic hypertension.)” The diseases are alike in that they both involve elevated “pressure.” In systemic hypertension, the elevated ‘pressure’ occurs within the blood vessels. In glaucoma, the elevated ‘pressure’ occurs within the eye. Although there is no “cure” for systemic hypertension, many medications are available to “treat” the disease. These treatments may be necessary throughout a person’s life. Similarly, glaucoma has no “cure,” but rather many different treatments. Patients with glaucoma usually need treatment from the time they are diagnosed until death. Treatments for glaucoma include medications (oral & eye drops), laser procedures, and surgeries. One or more of these treatments may be necessary during an individuals’ lifetime. Although laser procedures and surgeries are quite effective in treating the disease, neither of these modalities can “cure” glaucoma. Because glaucoma is a “chronic” condition, we usually attempt to treat the disease conservatively prior to recommending laser or surgical options. Conservative treatment involves the daily use of one or more types of eyedrops. In more severe cases, conservative treatment may include both eyedrops and oral medications. The use of oral medications in the treatment of chronic glaucoma has become less common than two decades ago. The oral medications have significant side- effects, which limit their use to brief periods of time.

UNDERSTANDING GLAUCOMA?

To understand glaucoma, we must think of the eye as a sink. The eye has a faucet and a drain. This faucet produces a clear fluid called aqueous humor. Aqueous humor is necessary to keep the eye formed and nourished. The drain removes the aqueous humor as rapidly as it is produced. In healthy eyes, the drain removes fluid at the same rate it is produced. Under these conditions, the sink does not become “overfilled.”
Elevated intraocular pressure occurs when the drain becomes damaged or clogged. Aqueous humor cannot leave the eye as fast as it is produced. As a consequence, aqueous humor “backs up” and starts over-filling the eye. This over-filling results in increased intraocular pressure.

The elevated intraocular pressure places stress on many parts of the eye. The part of the eye which is most vulnerable to increased pressure is the “optic nerve.” The optic nerve is very much like a fiber-optic cable, connecting the eye to the brain. The eye is like a camera, which captures images. Information about the image is transferred to the brain via the optic nerve. The brain interprets and processes this information. The result of this processing is sight. Thus, it is our brains, not our eyes, which allow us to “see.” Damage to the optic nerve interrupts communications between the eye and the brain thereby leading to sight loss. Thus, glaucoma is defined as “optic nerve damage.” In most instances, glaucoma is caused by elevated intraocular pressure. Elevated intraocular pressure occurs because the eye loses its ability to properly drain fluid.

WHAT CAUSES THE DRAIN TO BE DAMAGED?

The exact mechanisms by which the drain becomes clogged are not always known. In heart disease, we know that arteries become “clogged” due to increased cholesterol and fat in our diet. Thus, we are instructed to eat a low fat diet to help prevent clogging of the arteries. In glaucoma, we do not know what actually causes damage to the drain. Clogging of the eye’s drain is NOT related to our diet. Additionally, clogging of the eyes’ drain is not related to any behaviors or activities, which we engage in during our lifetime. The onset and severity of glaucoma cannot be altered by dietary modification, increased exercise, improved sleep patterns, or healthier diet. Stress levels have not been directly correlated with elevated intraocular pressure.

There are some factors, which are known to cause clogging of the drain. Moderate to severe trauma to an eye can damage the drain and lead to glaucoma. Eye surgery for conditions other than glaucoma may in rare instances lead to damage to the drain and ultimately lead to glaucoma. Use to corticosteroids (prednisone, dexamethasone, cortisone) can lead to clogging of the drain, and increased intraocular pressure. Steroids taken orally, inhaled, injected, topically (eye drops,) or placed on the skin may result in increased intraocular pressure if used for prolonged periods. People who come from families with a strong history for glaucoma probably have a “genetic” predisposition to the disease. This is not to say that every person who has a parent or grandparent who has or had glaucoma will get the disease, but they certainly have a greater chance of developing glaucoma than the average person.

WHAT ARE THE MOST COMMON RISK FACTORS FOR GLAUCOMA?

1. RACE: African Americans are at least 4 times more likely to develop glaucoma
2. DIABETES: Diabetics are more likely than non-diabetics to get glaucoma
3. MYOPIA: Nearsighted people are more likely to get glaucoma
4. AGE: People older than 65 are more likely than those under 65 to get glaucoma
5. FAMILY HISTORY: Having a 1st or 2nd degree relatives are at greater risk
6. CENTRAL CORNEAL THICKNESS: Individuals with thinner than average central corneas are at greater risk for developing glaucoma.

I HAVE ELEVATED INTRAOCULAR (EYE) PRESSURE. DOES THAT MEAN I HAVE GLAUCOMA?

The answer is no. Elevated eye pressure alone does not mean that a person has glaucoma. Remember, that glaucoma is defined as “damage to the optic nerve.” Although the most common cause of optic nerve damage is elevated pressure, not all individuals with elevated pressure have glaucoma.

Some individuals can tolerate abnormally high pressures without suffering optic nerve damage. Conversely, some individuals develop severe optic nerve damage despite the fact that their intraocular pressures are within normal range. Although intraocular pressure plays a major role in the development of glaucoma, there are factors beyond pressure, which contribute to the disease. Glaucoma can only be diagnosed by an eye care physician. In addition, measuring intraocular pressure is not the only test which needs to be done in order to diagnose and treat glaucoma. Assessment of an individuals’ peripheral vision, and sophisticated analysis of the optic nerve, are required to make the diagnosis of glaucoma.

WHAT PRESSURE IS CONSIDERED NORMAL?

We define the “normal” range of pressure to be 10 to 20mm Hg. Pressure is measured in millimeters of mercury. Over all races, the median pressure is 16mm Hg. This is considered “normal.” However, what is “normal” for one person may be quite “abnormal” for another person. Each individual has a unique range of “acceptable” pressures.

For some people, a pressure of 16mm Hg is considered too high. We consider patients in this group as having a unique type of glaucoma labeled “low tension glaucoma.” Patients with low-tension glaucoma seem to develop optic nerve damage despite the fact that their eye pressures consistently measure within the normal range (10-20mm Hg.) Exactly why these individuals develop optic nerve damage (glaucoma) despite having pressures within the normal range is unclear. These individuals tend to have factors other than elevated intraocular pressure, which contribute to their optic nerve damage.

Ocular hypertensive patients represent the other end of the spectrum. These patients have elevated pressures (20mm Hg or greater) but do not have optic nerve damage. Ocular hypertensives can have high eye pressures (20’s-30’s) for many years or even a lifetime and never develop glaucoma. The factors which make some eyes immune to elevated pressures remain unclear. What is clear, however, is that not every individual with increased pressure requires treatment. Additionally, not everyone with pressures in the normal range is immune from developing glaucoma.

HOW DO YOU DIAGNOSE GLAUCOMA?

As you can see from the above discussion, simply measuring eye pressure does not guarantee a correct diagnosis. As we have stated, glaucoma is defined as damage to the optic nerve. Damage to the optic nerve initially leads to loss of peripheral vision. If the disease is allowed to progress, patients ultimately suffer loss of central vision. In general, damage to the optic does not cause “blurry” vision. Patients with advanced glaucoma may still be able to read the smallest letters on the eye chart. A patient’s ability to read the eye chart tells us very little about the health of the optic nerve. Fortunately, we do have sensitive tests of optic nerve function other than reading the “eye chart.”

Peripheral vision is lost in the early stages of glaucoma. The loss of peripheral vision may be so subtle that the individual is not aware of this condition until late in the disease. For this reason, glaucoma is called “the silent thief of sight.” As the disease progresses, the loss of visual field can move away from the periphery toward the center of vision. Classically, we say that glaucoma can cause “tunnel” vision. You can demonstrate this by closing one eye, and using the open eye to look through a tube such as the cardboard cylinder on the inside of a roll of aluminum foil. If you do this, you will notice that your vision straight ahead may be normal. You will also notice that you cannot see much above, below, or to either side of the object you are focusing on. This gradual loss of peripheral vision can become very disabling. Driving may become difficult due to an inability to detect cars on either side. Changing lanes and merging onto the highway become challenging tasks. Because the disease often progresses slowly, the person experiencing the visual field loss is rarely aware until quite late in the disease process.
We can test peripheral vision using what we call a visual field machine or perimeter. This machine is basically a giant computer screen shaped like a large bowl. The patient is positioned so that their head is placed in the center of this bowl. One eye is patched closed. The other eye fuses on a target at the center of the bowl. Small lights are then flashed on the computer screen. The patient pushes a small hand-held button when he or she sees the flashing light. Using lights of varying size and intensity we can make an accurate map of the patients’ peripheral vision. The results of this test allow the doctor to judge the “health” of the optic nerve. This assessment is a vital piece of information in diagnosing glaucoma and following its course over time.

The first two pieces of information needed to make a diagnosis of glaucoma are the intraocular pressure and the visual field test. The third piece of information needed to make a diagnosis of glaucoma is the appearance of the optic nerve and the nerve fiber layer. There are many tools available to directly evaluate the optic nerve and nerve fiber layer. Optic nerve imaging is best accomplished through a dilated pupil with special instrumentation. Images of the optic nerve are obtained with both a standard camera, as well as a laser imaging system. Baseline images should be obtained anytime glaucoma is suspected. As the patient is followed over time, repeat images are obtained and comparisons to the baseline studies are used to assess stability or progression of the disease.

CENTRAL CORNEAL THICKNESS

We have recently become aware of the fact that the thickness of the central cornea may play a role in predicting one’s risk for developing glaucoma was well as the risk for glaucomatous progression in patients with an established glaucoma diagnosis.

Measurement of corneal thickness is called “pachymetry.” Pachymetry is not a new ophthalmic test. However, its use in patients at risk for glaucoma is growing. A recently published study entitled “The Ocular Hypertension Treatment Study” (OHTS) has suggested that thinner corneas are a strong predictor of glaucoma development. The study also suggested that thicker corneas may have a protective effect.

The exact relationship between corneal thickness and glaucoma is not clearly defined at this time. What is understood, however, is that all patients at risk for developing glaucoma should have baseline measurements of their corneal thickness obtained and recorded for further study.

CONCLUSIONS

Glaucoma represents a number of disease states all of which are defined by death of optic nerve cells. The most common cause of optic nerve cell death is elevated eye pressure. However, nearly 25% of patients diagnosed with glaucoma do not show evidence of elevated eye pressure.
Accurately diagnosing glaucoma involves measurement of eye pressure on numerous days, at various times during the day. Additionally, the optic nerve must be imaged with standard photography or more recently developed scanning-laser cameras. Measurement of optic nerve function in a given individual can be obtained by performing “visual field” testing. Finally, measurement of corneal thickness is rapidly becoming incorporated into the work-up of all patients who are at risk for the development of glaucoma.

The results of all of the above tests are required to properly evaluate an individual at risk for developing glaucoma. Additionally, many of these tests are repeated at least annually to track to the health of the optic nerve over time. No single test alone can diagnose glaucoma. Timely diagnosis of glaucoma can be made only after careful evaluation of the above measurements in conjunction with the physician’s clinical judgment.

The following chapter is a guide to glaucoma surgery.  I have created this guide to help prepare patients for glaucoma surgery.  It is intended to help patients understand the “why” and “how” of glaucoma surgery.

OVERVIEW:

Surgical procedures for glaucoma have been evolving over the past 100 years.  Over the past 25 years, we have made large strides in improving surgical techniques and outcomes.  Glaucoma surgery is intended to lower the intraocular pressure (eye pressure.)  By lowering the eye pressure, we attempt to slow down progression of the disease.  Glaucoma is defined as damage to the optic nerve.  Abnormally elevated eye pressure is the most common cause of glaucomatous optic nerve damage.  Some patients develop glaucomatous optic nerve damage despite the fact that they have intraocular pressures within normal range. These patients are said to have “low tension glaucoma.”     Healthy people, who do not have glaucoma, have eye pressures ranging from 10mm to 20mm Hg.  The average pressure among American adults is 16mm Hg.  Therefore, glaucoma surgeries are intended to lower the eye pressure to 16mm Hg or less.  Surgery attempts to lower eye pressure by creating a new “drain” to allow aqueous fluid to leave the eye. Fluid which has exited the eye through the new drain collects in a cyst-like cavity called a “bleb.”  From here, the fluid enters the venous circulation (blood vessels) and leaves the orbit.

Roughly 15 to 25% of patients who have glaucoma do not have elevated pressures.  These patients develop damage to their optic nerves even though the eye pressure rarely reaches the mid-twenties.  These patients have what we call “low tension glaucoma.”   The types of surgeries performed on these patients are similar to the surgeries performed on patients with elevated pressures.  The main difference in surgery for “low tension glaucoma” is that we are attempting to lower the eye pressure to 12mm Hg or less.  This is a more aggressive reduction than we aim for in glaucomas due to elevated pressures (16mm or less.)

WHAT SHOULD I EXPECT FROM GLAUCOMA SURGERY?

Glaucoma surgery attempts to lower the eye pressure by various methods.  These methods will be clearly described in the following sections.  Regardless of the method used, it must be clear to patients that it takes on average 3 to 6 weeks to recover from surgery.  This does not mean that the patient must be a “couch potato” during this period, but rather that they must simply “take it easy” during this recovery period.  Many patients are comfortable driving one to two weeks after surgery.  Some patients, however, like to wait at least a month to 6 weeks prior to driving.

IS THERE PAIN DURING OR AFTER GLAUCOMA SURGERY?

Patients who undergo glaucoma surgery usually do not experience significant pain during or after the surgery.  Like any surgery, many patients experience mild discomfort for a few weeks following surgery. Strong pain medication is not commonly needed.  Most patients who undergo glaucoma surgery can achieve good pain relief with Tylenol.

The most common complaint patients express after glaucoma surgery is that they feel a “scratchy” sensation for the first 4 to 6 weeks.  This is normal after glaucoma surgery! Patients are actually feeling the stitch that is used to close the surgical wound.  This stitch is made of an absorbable material.  This stitch dissolves over a period of 4 to 6 weeks.  The stitch does not need to be “removed” because is will dissolve automatically.  The “scratchy” sensation can be minimized by using artificial tears.  Some patients also use lubricating eye ointments to improve their comfort.

IS THERE BLURRY VISION AFTER GLAUCOMA SURGERY?

Patient’s may experience blurry vision for the first 3 to 6 weeks following surgery.  The blurry vision can be very upsetting to patients who do not expect this.  However, if the 3 to 6 week recovery period is clearly explained and emphasized to the patient, many patients do not have difficulty during this period.

WILL I NEED EYEDROPS AFTER GLAUCOMA SURGERY?

Most patients do not require “glaucoma” eye drops after surgery.  They do however, require three types of post-operative eye drops for the first 2 to 3 months following surgery. They types of drops needed include:
1.    An antibiotic
2.    An anti-inflammatory (usually prednisone)
3.    A medication to dilate the pupil (this is used to help keep the eye comfortable.)

These three types of drops are used for roughly two to three months after surgery.  They allow the eye to heal at a controlled speed, prevent infection, and keep the eye relatively pain-free.  These medications are rarely used beyond 3 months following surgery

WHY DO WE PERFORM GLAUCOMA SURGERY?

Glaucoma surgery is an effective method of controlling the disease.  The surgeries, however, DO NOT  “cure” glaucoma.  The goals of surgery are to lower the pressure so as to protect the optic nerve from continued damage.  The surgeries do not restore sight which has already been lost.  The surgeries do not improve vision. The primary goal of glaucoma surgery is to slow the progression of the disease.

The pressure reduction achieved by surgery does NOT last forever.  Depending upon the type of surgery performed, a patient can hope to have their pressure lowered from a period of 6 months to 10 to 15 years.  There are a host of reasons why glaucoma surgeries are not permanent.  The most common cause for failure of glaucoma surgery is scarring of the newly created drainage passage.  Medications are used to minimize scarring for the first few months following surgery.  Over the course of a decade, there is little we can do to eliminate scarring altogether.
It is important to remember that recovery takes between 3 to 6 weeks following surgery.  Many patients begin to worry that they are not healing properly if they are not completely healed by two to three weeks.  It is important to share your fears with your doctors and allow them to alleviate any fears, which may develop after surgery.

WHAT TYPES OF GLAUCOMA SURGERY ARE THERE?

1.    Trabeculectomy
2.    Glaucoma Drainage Devices (Aqueous shunts)
3.    Non-penetrating filtration procedures (Aqua Flow)
4.    Diode laser cyclodrestruction

I will now outline each of these surgeries.  The type of surgery chosen depends on the type and severity of glaucoma.  Each patient has a different degree of disease.  The surgeon will choose the type of procedure to perform based upon each individual case.

Each surgery has advantages and disadvantages.  There is no “perfect” surgery.  The goal is to choose the appropriate procedure for each individual patient.

GLAUCOMA SURGERY-TRABECULECTOMY

Glaucoma therapy is directed at protecting the optic nerve and preserving visual function.  At present, this goal is achieved by lowering intraocular pressure using medications, laser treatments, or surgeries.  In general, surgery is reserved for patients who have glaucoma, which has not been well controlled on medications, and have had complete laser treatment.  Laser treatments are usually performed after a patient’s pressure becomes uncontrolled on a maximally tolerated medical regimen (MTMR.)

Although laser treatments can be effective, the pressure reduction they produce is not permanent.  When a patient has failed medical therapy, they usually undergo laser therapy.  When laser therapy in conjunction with, or in place of medical therapy fails, we resort to surgery.  Although surgery has historically been the last treatment on our list, this thinking is changing rapidly.  With advances in surgical devices and techniques, the role of surgery is rapidly growing.  Surgery is no longer viewed as a “last-resort.”  In certain cases, surgery may be a better “first step” than either medications or laser treatments.

Glaucoma surgeries attempt to make a relatively permanent “drain” in the eye.  This drain will serve to remove aqueous humor from inside the eye to an extra-ocular reservoir.

The creation of a hole or fistula is called a trabeculectomy.  Trabeculectomy first gained widespread notoriety in the 1970’s.  The procedure has been performed continuously since that time.

WHAT DOES A TRABECULECTOMY ENTAIL?

With glaucoma filtering surgery, trabecular meshwork and sclera are excised, creating a fistula through which aqueous humor drains from the anterior chamber.  The aqueous humor accumulates in the subconjunctival space, forming a filtering bleb.   Although it is not known with certainty, aqueous humor within a functioning filtering bleb is thought either to drain through the conjunctiva into the tear-film, or to be absorbed from capillaries within episcleral and subconjunctival tissue and join the systemic circulation.

INDICATIONS FOR TRABECULECTOMY:

For most ophthalmic surgeons, the indications are as follows:  A patient with glaucoma on maximum tolerable medical therapy who has had maximal laser benefit and whose optic nerve function is failing or is likely to fail.

The surgeon must be certain the patient has glaucoma, and not just ocular hypertension or nonglaucomatous optic neuropathy.  This determination implies characteristic damage to the optic nerve, visual field, or both.

SURGICAL TECHNIQUE:

Trabeculectomy is, in essence, a filtering procedure designed to divert the aqueous humor through an eye-wall fistula (hole)  to a subconjunctival filtering reservoir, the filtering bleb.  The goal of glaucoma filtering surgery, like that of medical and most laser therapies, is to lower the intraocular pressure (IOP) below the threshold that causes optic nerve damage.

THE ROLE OF ANTI-METABOLITES:

The use of anti-metabolites during filtration surgery has greatly enhanced surgical success rates in high-risk eyes. These chemicals are applied to the eye at the time of surgery.  They serve to decrease scaring of the surgically created wound.  This allows the newly created glaucoma drain to remain open.   Unfortunately, they are not without a significant downside. They have been shown to increase the rate of post-operative infection.  In addition, they increase the incidence of postoperative wound leak.  Intra-operative or post-operative use of 5-fluorouracil (5-FU) or mitomycin C (MMC), to limit scarring following glaucoma filtering surgery can improve the surgical outcome of an eye with a poor prognosis.

RISKS OF TRABECULECTOMY:

The risks of glaucoma surgery include bleeding, infection, blindness, and loss of the eye.  These risks are not unique to glaucoma surgery.  However, eyes with glaucoma are usually “sicker” than eyes without glaucoma.  Despite these risks, the benefits of long-term pressure reduction are great.  Numerous scientific studies have repeatedly demonstrated that patient’s whose pressures are lowered by at least 30% from their untreated levels have better preservation of visual function over the course of their lifetime.

POST-OPERATIVE COURSE:

Glaucoma surgery attempts to lower the intraocular pressure without the aid of glaucoma medicines.  During the early postoperative period, the intraocular pressure can by variable.  In some patients, the pressure is quite low.  In other patients, the postoperative pressure can be higher than it was before surgery.

When the pressure fluctuates, often a patient’s vision will fluctuate.  Patients often experience blurred and frankly poor vision for the first 6 weeks after surgery.  Fortunately, by the beginning of the second month following surgery, vision usually returns to its preoperative level and stays there.  One of the paramount goals of glaucoma surgery is to minimize an individual’s dependence on glaucoma medication.  Although this is not achieved in 100% of cases, it is certainly attainable in a good number.    The following pages illustrate and describe a surgical trabeculectomy.

POST-OPERATIVE PATIENT  INFORMATION

TRABECULECTOMY SURGERY:

1. TRABECULECTOMY lowers the pressure inside the eye!  They do not cause the fluid to drain into your tears.  The fluid, which is drained out of your eye, is shunted to the back of the eye, and from there it enters the venous system to be removed from the eye as it mixes into the bloodstream.

2.  BLURRY VISION IS NORMAL AFTER THIS SURGERY!
Your vision will be very blurry for the first 3 to 6 weeks following this surgery.  Many patients become anxious during the first month after surgery because their vision does not return to normal immediately after surgery.  I cannot over-emphasize that it is normal to have very blurry vision for 6 full weeks following the surgery.  It is important to keep this in mind so as not to become worried that something has gone wrong with your surgery.

3. WATERING OF THE EYE IS NORMAL AFTER SURGERY!
Tearing, watering, and mattering are all common complaints after this type of surgery.  The excessive tearing and watering will resolve on their own over the first 3 to 6 weeks.  It is not a permanent problem.  Be patient, this problem is very common, but always resolves spontaneously over time.

4. A SCRATCHY OR “SANDY” SENSATION IS NORMAL AFTER SURGERY!
Glaucoma surgery requires stitches (sutures).  The stitches dissolve spontaneously.  It takes about 3 to 6 weeks for the stitches to dissolve.  During this period, you may feel the stitch scratching the eye.  This is NORMAL!  Some people feel this scratchy sensation a few days after surgery; some do not experience it until many weeks after surgery.  Do not be alarmed if you experience this.  One way to lessen the discomfort is to use an eye ointment, which your doctor can prescribe for you in the office, or call it in to your pharmacy.  There are also over the counter ointments available, which your doctor may recommend.  The ointments lubricate the stitches and minimize the friction between the stitches and your eyelids.  The ointments help the comfort of the eye but can cause blurry vision because they are very thick.  They are very helpful if used before going to sleep because they will have minimal effect on your vision, and keep the eye moist when you sleep.  They might cause your eye to be stuck shut in the morning, but this can easily be removed with a cool compress.

5. YOU WILL NOTICE A CYST ON THE UPPER PART OF YOUR EYE!
This cyst is called a “bleb.”  This is a normal occurrence.  In fact, we hope to have a good-sized bleb because this is where your new drain is.  The bleb often looks like a blister.  Do not be alarmed if you see it.  It is supposed to be there!

6. SEVERE PAIN, HEADACHE AND NAUSEA ARE NOT NORMAL!
MUCUS, PUS, OR GREEN-YELLOW DISCHARGE IS NOT NORMAL.
If you experience any of these, please call our office immediately at (602)-955-1000.

GLAUCOMA SURGERY-GLAUCOMA DRAINAGE DEVICES (GDD) OR AQUEOUS SHUNTS

During the past two decades, glaucoma drainage devices (GDD’s) have been increasingly used in the treatment of glaucoma.  Approximately 5000 GDD’s are used in the United States annually.  Most GDD’s consist of a segment of silicone rubber tubing attached to a rigid plastic or flexible silicone rubber explant.

As previously discussed, glaucoma occurs when the pressure in the eye becomes elevated. The pressure usually becomes elevated due to damage to the natural drain within the eye.  GDD’s work by “shunting” excess fluid out of the eye through the silicone rubber tubing.  Once removed from the eye, the fluid joins with venous blood, which is returned to the heart

Over the past 5 years, the use of GDD’s has grown rapidly.  This increase is due to both improved devices, as well as improved surgical techniques.

GDD’s are less prone to failure than traditional “trabeculectomy” because they are less effected by post surgical scarring.  An important advantage which GDD’s have over trabeculectomy is that they do not leave the eye as susceptible to infections following otherwise successful surgery.

The following illustration displays several types of GDD architecture.

The first GDD was the Malteno glaucoma implant, which initially appeared in 1969.  Commercially manufactured GDD’s currently available in the U.S. included both “valved” or “flow-restricted” designs (Ahmed, Krupin) and “nonvalved” (Malteno, Baerveldt) designs.  While differing in size, shape, and details of instillation, all of these devices share common features and utilize the same physiologic principles.

GLAUCOMA SURGERY-GLAUCOMA DRAINAGE DEVICES

HOW TO GDD’S WORK?

The human eye produces a clear, water-like, fluid called aqueous humor.  In a healthy individual, this fluid is drained out of the eye at the same rate it is produced.  In patients with glaucoma, the eye loses its ability to drain the fluid out as fast as it is being produced.  As a consequence, the aqueous humor accumulates in the eye and the pressure within the eye increases.  The increase in pressure leads to damage of structures within the eye.  The structure within the eye which is most susceptible to increased pressure is the optic nerve.  Thus, glaucoma is defined as damage to the optic nerve resulting from increased intraocular pressure.

As we have discussed, patients with glaucoma usually have a damaged drainage system.  GDD’s lower pressure because they allow the excess fluid to bypass the damaged drainage system.  GDD’s work by “shunting” fluid out of the eye.  They consist of a one way drain attached to a straw like piece of tubing.  The drain is referred to as the “plate.”  The tubing is surgically inserted into the eye.  It runs from inside the eye to the plate, which is sutured onto the outside of the eye. Thus, aqueous humor is shunted from inside the eye to the plate, where it is absorbed by blood vessels, which return it to the systemic circulation.

INDICATIONS:

The general indications for installing GDD’s include failure of conventional therapies such as medications, laser trabeculoplasty, and standard trabeculectomy with or without antifibrotic agents.

GLAUCOMA SURGERY-GLAUCOMA DRAINAGE DEVICES

POST-OPERATIVE COURSE:

GDD’s have demonstrated, as do some trabeculectomies, a period of elevated pressure before the ultimate lowering occurs.  Intraocular pressure often falls initially, and then rises to preoperative levels or even higher for weeks before falling again.  Resumption of medications is indicated to minimize the transient pressure rise.

POST-OPERATIVE MEDICATIONS:

Post-operative medications following GDD surgery include topical corticosteroids such as Pred Forte 1% from 4 to 6 times a day.  In addition, topical antibiotic (Ciloxan, Oxuflox) drops should be used. Glaucoma medications will usually need to be resumed promptly after placement of a GDD, pending spontaneous or surgical opening of the tube as the absorbable ligature dissolves or is cut with a laser

WHAT ARE THE MOST COMMON COMPLICATIONS?

Complication rates for GDD’s have fallen drastically over the past decade due to improved knowledge and experience with the devices.  In general, the most common complications seen with any ocular surgery are bleeding, or infection, which in the worst-case scenario, can lead to total blindness and loss of the eye. The most common short term complication is low pressure.  The major long-term problems seen with GDD’s are double vision, and corneal decompensation.  The reasons for double vision are varied and not always predictable.  Corneal decompensation occurs when the tube migrates and comes into contact with the inner surface of the cornea.  Both of these problems can be surgically remedied.  Double vision can be remedied by removing the GDD.  Corneal decompensation can be improved by corneal transplantation.

SUMMARY:

In summary, GDD’s offer an excellent alternative to conventional filtration surgery.  Surgery should be performed by a surgeon with broad experience with GDD’s.  Once functioning, GDD’s can provide good long-term intraocular pressure reduction and glaucoma control.  Unfortunately like all glaucoma procedures, the pressure control produced by these devices is not always permanent.  However, GDD’s offer the most predictable long-term pressure control for glaucoma patients.

GLAUCOMA SURGERY-GLAUCOMA DRAINAGE DEVICES

SURGICAL TECHNIQUE:

The white part of the eye is called the sclera.  The sclera is covered with a thin, film-like layer of clear tissue known as the conjunctiva.  Surgery involves opening the conjunctiva thereby exposing the sclera. The drainage device is then placed in a selected quadrant and sutured to the sclera.  The tube is then inserted into the eye through a tract created by a small needle.  The tube is then temporarily closed off with an absorbable suture and anchored to the sclera.  The tube is then covered with a piece of donor sclera or pericardium.  The conjunctiva is then closed in a watertight fashion, completely covering the drainage device and the tube.

FIGURE  A.

The conjunctiva has been opened.  The supero-temporal Quadrant has been exposed.  The superior and lateral rectus muscles have been isolated.  The plate is placed under the superior rectus muscle.

FIGURE B:

The plate is placed under the lateral rectus muscle. You can see the tube attached to the plate.  In this picture, the tube has not yet been placed into the eye.

FIGURE C:

The tube has been placed into the eye.  The tube is covered with a square piece of donor sclera or pericardium.  As you can see, the tube sits in the anterior chamber (front of the eye).  The conjunctiva has not yet been closed.

POST-OPERATIVE PATIENT  INFORMATION

GLAUCOMA DRAINAGE DEVICE SURGERY:

ANDREW RABINOWITZ, M.D.

1. GLAUCOMA DRAINAGE DEVICES  lower the pressure inside the eye!.  They do not cause the fluid to drain into your tears.  The fluid, which is drained out of your eye, is shunted to the back of the eye, and from there it enters the venous system to be removed from the eye as it mixes into the bloodstream.

2. DOUBLE VISION IS NORMAL AFTER THIS SURGERY! .
It is not unusual to experience double or triple vision after this type of surgery.
The double vision is usually worst during the first 3 weeks and then slowly improves over the first 3 months.  Many patients become alarmed when they experience double vision, but I stress that this is a normal occurrence, and does not mean that something has gone wrong with your surgery.  Some people find that patching the eye for a few weeks makes the double vision go away.  There is not harm in covering the operated eye even during the daytime to lessen the double vision.  I often recommend this to patients who experience double vision.

3. WATERING OF THE EYE IS NORMAL AFTER SURGERY!
Tearing, watering, and mattering are all common complaints after this type of surgery.  The excessive tearing and watering will resolve on its own over the first 3 to 6 weeks.  It is not a permanent problem.  Be patient, this problem is very common, but always resolves spontaneously over time.

4. A SCRATCHY OR “SANDY” SENSATION IS NORMAL AFTER SURGERY

5. BLURRY VISION IS NORMAL AFTER THIS SURGERY!
Your vision will be very blurry for the first 3 to 6 weeks following this surgery.  Many patients become anxious during the first month after surgery because their vision does not return to normal rapidly.  I cannot over-emphasize that it is normal to have very blurry vision for 6 full weeks following the surgery.  It is important to keep this in mind so as not to become worried that something has gone wrong with your surgery.

6. IT TAKES 6 WEEKS BEFORE THE SHUNT LOWERS EYE PRESSURE!
The drainage device is used to control pressure by shunting fluid out of the eye.  The device, however, is designed to lower the pressure gradually over 6 weeks following surgery.  In fact, the drain does not work at all for the first month after surgery.  After that time, it slowly starts to drain out the fluid and lower the pressure.  By six weeks after surgery, the drain will be working at full capacity.

7. SEVERE PAIN, HEADACHE AND NAUSEA ARE NOT NORMAL!
If you experience any of these, please call our office immediately at (602)=955-1000.

GLAUCOMA SURGERY-DEEP SCLERECTOMY  WITH VISCOCANALOSTOMY (DSVC)

The most commonly performed glaucoma procedure in the United States is the trabeculectomy.  Trabeculectomy attempts to make a partial hole in the white part of the eye (sclera).  Aqueous humor drains through this hole into a small blister-like cyst known as the “bleb.”  Unfortunately, the bleb obtained in successful glaucoma surgery has many unfavorable characteristics.  Firstly, the bleb may be elevated, causing the patient to feel as though there is something in their eye.  Secondly, large blebs can grow onto the cornea and become cosmetically unacceptable.   Finally, blebs make the eye susceptible to severe infections.  The risks of developing a profound infection leading to blindness are much greater in eyes with functioning blebs.

Glaucoma surgeons have spent the past decade attempting to invent a glaucoma surgery which does not result in the creation of a bleb.  DSVC attempts to bypass the obstructed trabecular meshwork without creating a scleral hole or fistula.  DSVC is referred to as non-penetrating filtration because no hole is created in the eye as is done with trabeculectomy.

DSVC involves the creation of a drainage channel without creating a full thickness hole in the sclera.  Theoretically, this will greatly decrease the incidence of post-operative wound leaks and infections.  In addition, because no hole is made, the surgery is less susceptible to failure because scarring is less critical to the long-term success of the surgery.

DSVC is a surgery in its infancy.  The results of our initial experience with DSVC are encouraging enough to stimulate significant worldwide interest in his procedure.

I have performed over 200 of these procedures with promising results.  The rate of postoperative complications has been lower than that seen with trabeculectomy.  Bleb formation does occur in about 25% of cases.  These blebs however, are low lying, and usually disappear by 6 months.  The intraocular pressure has remained controlled even in
cases in which the bleb becomes extinct.
DSVC will not completely replace conventional filtration surgery.  However, it will likely assume a crucial role as an alternative to trabeculectomy.  DSVC may in fact become the treatment of choice in juvenile glaucomas, pigmentary glaucomas, and open angle glaucomas in myopic eyes.  Results of DSVC have been less favorable in far-sighted patients, and eyes with inflammatory glaucomas.

Further studies and refinement of the technique will undoubtedly push the envelope of glaucoma surgery.  DSVC offers an excellent alternative to trabeculectomy.  This is important in patients who have undergone unsuccessful trabeculectomy in one eye and require initial surgery in the fellow eye.

In glaucoma, hope springs eternal.  Clinical trials are underway for another novel glaucoma surgery, which involves using a synthetic “wick” to draw aqueous fluid out of the eye through a non-penetrating scleral reservoir.  We hope to participate in this international clinical trial in the coming months.  This would enable The Barnet Dulaney Eye Center to offer cutting-edge surgical treatment for glaucoma.

POST-OPERATIVE PATIENT  INFORMATION

DEEP SCLERECTOMY  SURGERY:

1. DEEP SCLERECTOMY lowers the pressure inside the eye.  The fluid, which is drained out of your eye, is shunted to the back of the eye, and from there it enters the venous system to be removed from the eye as it mixes into the bloodstream.  The fluid removed from your eye does not join with your tears.

2.  BLURRY VISION IS NORMAL AFTER THIS SURGERY!
Your vision will be very blurry for the first 3 to 6 weeks following this surgery.  Many patients become anxious during the first month after surgery because their vision does not return to normal rapidly.  I cannot over-emphasize that it is normal to have very blurry vision for 6 full weeks following the surgery.  It is important to keep this in mind so as not to become worried that something has gone wrong with your surgery.

3. WATERING OF THE EYE IS NORMAL AFTER SURGERY!
Tearing, watering, and mattering are all common complaints after this type of surgery.  The excessive tearing and watering will resolve on its own  over the first 3 to 6 weeks.  It is not a permanent problem.  Be patient, this problem is very common, but always resolves spontaneously over time.

4. A SCRATCHY OR “SANDY” SENSATION IS NORMAL AFTER SURGERY!
Glaucoma surgery requires stitches (sutures).  The stitches are self-absorbing.  It takes about 3 to 6 weeks for the stitches to dissolve.  During this period, you may feel the stitch scratching the eye.  This is NORMAL!  Some people feel this scratchy sensation a few days after surgery; some do not experience it until many weeks after surgery.  Do not be alarmed if you experience this.  One way to lessen the discomfort is to use an eye ointment, which your doctor can prescribe for you in the office, or call it in to your pharmacy.  There are also over the counter ointments available, which your doctor may recommend.  The ointments lubricate the stitches and minimize the friction between the stitches and your eyelids.  The ointments help the comfort of the eye but can cause blurry vision because they are very thick.  They are very helpful if used before going to sleep because they will have minimal effect on your vision, and keep the eye moist when you sleep.  They might cause your eye to be stuck shut in the morning, but this can easily be removed with a cool compress.

5. YOU WILL NOTICE A CYST ON THE UPPER PART OF YOUR EYE!
This cyst is called a “bleb.”  This is a normal occurrence.  The bleb often looks like a blister.  Do not be alarmed if you see it.  It is supposed to be there!

6. SEVERE PAIN, HEADACHE AND NAUSEA ARE NOT NORMAL!
MUCUS, PUS, OR GREEN-YELLOW DISCHARGE IS NOT NORMAL.
If you experience any of these, please call our office immediately at (602)=955-1000.

GLAUCOMA SURGERY:-TRANS-SCLERAL  LASER  CYCLOPHOTOCOAGULATION (CPC)

WHAT IS CPC?

The ciliary body is the structure that produces aqueous humor.  Aqueous humor is a clear liquid.  This liquid is responsible for keeping the eye formed.   Cyclodestruction is a treatment, which destroys cells of the ciliary body.  In so doing, the treatment attempts to shut down the production of fluid within the eye.  Cyclodestructive procedures are recommended in patients with advanced glaucomas and otherwise poor prognoses.  Often these patients have been relative failures of medical therapy and glaucoma filtering surgery. In many respects, CPC can be viewed as a “last-step effort to save the eye.”

The cyclodestructive procedures are also useful in patients in whom conventional surgery is contraindicated by their systemic health or local ocular condition.  Generally, these patients have little or no functional vision.  Reduction of intraocular induced pain in this clinical setting is an important indication.

WHO IS A CANDIDATE FOR CPC?

CPC is reserved for patients who undergone multiple eye surgeries including glaucoma surgeries who still have elevated eye pressure.  Often, these patients have lost a significant amount if not all of their vision

WHAT ARE THE INDICATIONS FOR THIS PROCEDURE?

1.    Persistently elevated eye pressure despite aggressive surgical treatment.
2.    A painful eye with little or no sight remaining.
3.    Uncontrolled glaucoma in a patient who is not a good surgical candidate.
4.    Reduction of pain in a blind eye.

HOW DOES THE LASER GET TO THE EYE?

The laser energy is delivered to the eye through a probe, which resembles a pen.
The entire procedure usually takes 2 to 5 minutes. The procedure is well tolerated because the patient is treated with a local anesthetic prior to the treatment.  The treatment does not require any incisions, sutures, or needles.

WHAT IS THE SUCCESS RATE OF CPC?

The results of CPC are generally quite good.  Most patients can be successfully treated with one to two sessions of laser therapy.  In severe glaucomas, the treatment may have to be repeated two to three times over the first year to obtain maximum pressure control.  One of the greatest advantages of the procedure is that it can be repeated as often as is needed.

WHAT ARE THE MAIN RISKS?

The most significant risk with this procedure is the eye pressure becomes too low and stays that way.  This is a very rare occurrence, and often not a problem because control of pain is usually the main indication for this procedure.  Like other eye surgeries, bleeding and infection are very low, but possible risks.