Author: eyestucson

As noted in the general glaucoma review, the vast majority of people with the disease have the open angle type, and most of these have what is known as primary open angle glaucoma, or POAG. The main feature of POAG, aside from elevated intraocular pressure (IOP) and visible damage to the optic nerve, is an otherwise normal eye. In other words, there are no other identifiable abnormalities to explain either the pressure or optic nerve damage. The cause or causes of POAG are largely unknown, though numerous genetic defects are being studied for their role in the disease.

A significant number of patients with open angle glaucoma have special forms of the disease, known as secondary open angle glaucoma. In these conditions, there are identifiable abnormalities responsible for the elevated intraocular pressure and associated damage. One such condition, pseudoexfoliation glaucoma, is described below.

Pseudoexfoliation Syndrome

Also known as Pseudoexfoliation Glaucoma, pseudoexfoliation glaucoma (PXFG) is probably the most common type of secondary open angle glaucoma, accounting for 10 to 25 percent of glaucoma worldwide. The disease is caused by production of an abnormal material within some of the tissues of the eye. This material ultimately ends up within the eye’s drainage system where it causes damage, essentially clogging the channels and raising intraocular pressure. While the exact cause of PXFG is not known, strong evidence suggests that one or multiple genetic abnormalities are responsible. Indeed, a recently identified gene has been found to be significantly associated with pseudoexfoliation. Further research will help us learn the exact role of this gene in the disease.

Diagnosis of PXFG is made by identifying the abnormal material, which looks a bit like dandruff flakes, on the iris or lens. It is important to have the pupils dilated, as the material may be missed otherwise. Visualizing the material can be difficult, particularly early on in the disease, and it may not be found until years after the initial diagnosis of glaucoma is made. The presence of pseudoexfoliation, and the associated risk of glaucoma, increases with age.

Although very similar to POAG, PXFG does have a few unique features:

• While elevated IOP and optic nerve damage tends to occur in both eyes symmetrically in POAG, it is often markedly asymmetric in PXFG, with one eye affected much more than the other. Indeed, some patients with PXFG appear to have glaucoma in only one eye.
• IOP fluctuates more widely and pressures run higher in PXFG. Furthermore, IOP is often more difficult to control with medications than in POAG. Medical treatment will often require more than one drug to control IOP.

PXFG is treated similarly to other types of open angle glaucoma. Medications are usually the first option. However, as noted above, medications are often less effective than in POAG. Laser trabeculoplasty can have a very good effect in PXFG, often dropping the IOP significantly. The drop in pressure from trabeculoplasty is temporary, however, and IOP may begin to elevate again within a few years. Ultimately, surgical intervention may be required in at least one eye.

Not every patient with pseudoexfoliation will develop glaucoma. There is about a 70 to 85% chance that elevated IOP and glaucoma will occur, and the risk increases with age. If pseudoexfoliation material is identified in your eye during an examination, observation 2-3 times per year is indicated to watch for signs of rising pressure.

As noted in the section on glaucoma, the vast majority of people with the disease have the open angle type, and most of these have what is known as primary open angle glaucoma, or POAG. The main feature of POAG, aside from elevated intraocular pressure (IOP) and visible damage to the optic nerve, is an otherwise normal eye. In other words, there are no other identifiable abnormalities to explain either the pressure or optic nerve damage. The cause or causes of POAG are largely unknown, though numerous genetic defects are being studied for their role in the disease.

A significant number of patients with open angle glaucoma have special forms of the disease, known as secondary open angle glaucomas. In these conditions, there are identifiable abnormalities responsible for the elevated intraocular pressure and associated damage. One such condition, pigment dispersion syndrome, is described below.

Pigment Dispersion Syndrome and Pigmentary Glaucoma

Pigment Dispersion Syndrome (PDS) with pigmentary glaucoma is another relatively common form of secondary open angle glaucoma. This condition typically occurs in younger patients, between the ages of 20 and 45. Patients are more often male and tend to be nearsighted.

In PDS, small pigmented (brown colored) granules are rubbed off the back of the iris due to abnormal contact between the iris and the zonules, the fibers which hold the lens in place. This is believed to be caused by an abnormality of iris anatomy in which the iris is positioned too far back within the eye. Why this develops is not known. The released pigment then floats about the eye, being deposited in multiple locations, including within the trabecular meshwork and drainage channels where it causes damage and may lead to elevated IOP.

Diagnosis of PDS is made by identifying typical patterns of pigment deposition within the eye, as well as other common features. Pigment is frequently seen on the cornea in a spindle-shaped pattern (known as a Krukenberg’s spindle) and may be seen on the front or back surface of the lens. Often quite dense and dark, pigment is always found within the trabecular meshwork. Slit-like defects in the iris, known as transillumination defects, are typically seen to some degree, and represent areas where pigment has been extensively worn away by rubbing against zonules. The front of the eye, called the anterior chamber, is often abnormally deep in appearance due to the backwards displacement of the iris.

IOP in pigmentary glaucoma can fluctuate widely, often becoming quite high. In fact, IOP “spikes” have been noted to occur spontaneously or, in some cases, after exercise due to sudden release of large amounts of pigment. While most types of glaucoma seldom have any acute symptoms, these rapid elevations of pressure can lead to pain and blurred vision, at times with halos seen around lights. Anyone diagnosed with PDS should report such episodes to their eye doctor, as adjustments in treatment might be indicated.

Not everyone with PDS develops elevated IOP or glaucoma. In fact, there appears to be no direct correlation between the amount of pigment in the trabecular meshwork and the level of intraocular pressure. The reasons for this are not understood, but it is believed that pigmentary glaucoma requires more than just pigment release, that there must be some other abnormality of the drainage channels that has not yet been identified. If PDS is identified during an examination and the optic nerves and IOP are normal, a few additional pressure checks may be performed over the next several months. If IOP remains normal over multiple visits, observation every 6 to 12 months may be indicated.

Treatment of pigmentary glaucoma is similar to that of other types of open angle glaucoma. Medications are usually the first option, often with multiple medications required to control pressure fluctuations. Laser trabeculoplasty can have a very good effect in PDS, often dropping the IOP significantly. The drop in pressure from trabeculoplasty is temporary however, and IOP may begin to elevate again within a few years. Furthermore, patients with PDS occasionally experience substantial spikes in IOP after laser treatment, and at times pressure elevation may be sustained. Therefore, caution must be taken when performing this procedure. Finally, glaucoma filtering surgery such as trabeculectomy can be performed quite successfully.

When medications or laser procedures fail to adequately control intraocular pressure (IOP), or if side effects prevent the continued use of medications, surgery becomes necessary to achieve the desired level of IOP. Surgery for glaucoma lowers IOP by either increasing the flow of fluid out of the eye or by decreasing the production of intraocular fluid.

It must be remembered that optic nerve damage and subsequent loss of vision caused by glaucoma cannot be reversed. Thus, the point of surgery is not to improve or restore vision, but rather to prevent further vision loss. Currently there is no glaucoma treatment that can restore vision already lost to the disease. For this reason, early diagnosis and treatment are vital.

This article describes Micro-Invasive Glaucoma Surgeries, procedures that may be an option for some patients with certain types of glaucoma. A comprehensive evaluation by a surgeon who performs these procedures is necessary to determine the best option for any given patient.

Introduction

Traditional glaucoma surgery, known generally as filtering surgery, drains fluid from the eye by creating an artificial pathway through the sclera, the white of the eye. These procedures are very effective at reducing intraocular pressure (IOP), and in some cases are the only good options. However, due to the nature of the artificial connection between the inside and outside of the eye, they are associated with several potential complications, some of which can be serious.

On the other hand, Micro-Invasive Glaucoma Surgery, or MIGS procedures, work by attempting to reestablish good flow through the eye’s normal drainage system or, in some cases, by diverting fluid between the layers of the eye. While typically not quite as effective as filtering surgery at reducing the eye pressure, these procedures are generally faster to perform, offer a much shorter healing period, have less impact on early post-operative vision, and have fewer overall risks, both short and long-term. Additionally, they do not limit the future performance of other procedures, allowing for a stepwise approach to lowering the IOP while not “burning any bridges” for future surgeries that may be needed.

Schlemm’s Canal-Based Procedures

Schlemm’s canal is the primary drainage channel by which aqueous humor, the intraocular fluid that is continually being produced, leaves the eye. This canal runs 360 degrees around the front of the eye, where the iris (the colored part of the eye) meets the sclera (the white of the eye). In many cases of open angle glaucoma, it is believed that this canal is not functioning properly. In simplistic terms, the canal is clogged. The actual defect is thought to lie within the trabecular meshwork, a network of tissue that lines the entrance into the canal. Several MIGS procedures aim to bypass the trabecular meshwork and allow fluid to enter Schlemm’s canal directly, thereby increasing drainage of fluid from the eye and lowering the intraocular pressure.

• Micro-bypass stents: Currently there are two types of stents available for implantation in the United States, the Glaukos^® iStent^®, which now in its third generation is known as the iStent Inject^®, and the Ivantis^® Hydrus^® microstent. Initially approved by the FDA in 2012 and 2018, respectively, these stents are inserted through the trabecular meshwork and into Schlemm’s canal in order to drain aqueous humor more effectively. Currently, implantation of these stents is only reimbursed by Medicare and most insurance companies when combined with cataract surgery. Stents will not be paid for if implanted as a separate procedure. Though the design of each device differs somewhat, studies suggest similar efficacy overall. While one recent study (the COMPARE trial, published April 2019) found the Hydrus to be more effective than the original iStent design, no clear head-to-head data is currently available comparing the Hydrus and the newer iStent Inject. On average, however, these stents lead to pressure reduction of one to two millimeters of mercury beyond that produced by cataract surgery alone and decrease the need for medications by one to two drugs. There is minimal additional risk to the implantation of these stents, and no impact on the normal healing period for cataract surgery. In general, blood thinners do not need to be stopped. The decision regarding which stent to implant is best made based upon the anatomy of the individual eye, conditions found at the time of surgery, and the surgeon’s familiarity with each device.

• Ab-Interno Canaloplasty (AbIC): Another option for increasing the outflow of aqueous via the eye’s natural drainage pathways, this procedure dilates and cleans out Schlemm’s canal. A tiny catheter, or hollow tube, is inserted into the canal through the trabecular meshwork and passed 360 degrees around the entire eye, breaking adhesions and scar tissue that have formed over time. As the catheter is withdrawn, a thick liquid is injected into the canal, further dilating it and forcing out debris. This procedure is effective and reimbursed by insurances either combined with cataract surgery or when performed by itself. Several reasonably sized studies have shown pressure reductions of as much as 30%, or four to six millimeters of mercury, though actual reduction may be more or less than this. Complication rates are relatively low and generally mild, though bleeding is more likely than with stent implantation and therefore discontinuation of blood thinners is recommended for this procedure. Recovery to clear vision may be slightly delayed by a few days due to bleeding.

• Goniotomy: This procedure involves either cutting into or removing a variably sized section of the trabecular meshwork, allowing aqueous humor a more direct pathway into Schlemm’s canal. Overall, efficacy is similar to that of AbIC, though depends upon the extent of meshwork treated. As with AbIC, intraocular bleeding is more likely than with stent implantation. Thus, it is recommended that blood thinners be discontinued for this procedure. Again, recovery to clear vision may be slightly delayed by a few days due to bleeding.

Suprachoroidal Implants

As we have discussed, MIGS procedures attempt to reestablish good fluid drainage through the eye’s natural outflow system, while filtering surgeries abandon that system in favor of a surgically created bypass drain through the sclera, the white of the eye. More recently, however, a third option for aqueous drainage has been developed. Though a bit more difficult to conceptualize, these procedures take advantage of a pressure difference, or gradient, between layers within the eye, allowing fluid to drain away in a novel manner. Currently, none of these implants are FDA approved for use in the US, however their availability is anticipated in the next few years.

Trans-scleral Stents

Though these procedures do not quite fit the definition of Micro-Invasive Glaucoma Surgery, they do somewhat bridge the gap between MIGS procedures and traditional filtering surgery, and it seems logical to at least mention them here. Like filtering surgeries, aqueous humor is diverted from inside to outside the eye via a bypass through the sclera, forming what is known as a “filtering bleb.” However, much less cutting and manipulation of tissues is required when implanting these devices, with considerably shorter operative and recovery times. Some of the risks of traditional filtering surgery are reduced, though certainly not eliminated. Therefore, unlike other MIGS procedures that can be performed by nearly any eye surgeon trained appropriately, trans-scleral stents are generally implanted by surgeons experienced with glaucoma filtering surgeries and their post-operative management.

There is only one such device approved for use in the US by the FDA: the XEN45 glaucoma implant. Another such implant, known as the PreserFlo shunt, is expected to be approved in 2021.

Choosing a MIGS Procedure

In the United States, the majority of MIGS procedures are performed in combination with cataract surgery in order to gain better control of intraocular pressure and/or to reduce a patient’s dependence on pressure-lowering medications. Given the efficacy and extremely low risk of MIGS procedures, they ideally compliment cataract removal in patients who also have mild to moderate glaucoma. Additionally, these procedures are often an excellent stand-alone option for patients with glaucoma for whom medications and laser trabeculoplasty have failed to adequately control their disease, prior to considering more traditional filtering surgery.

  Ultimately, which procedure is chosen depends on several factors, as previously noted. These include overall patient health and use of blood thinners, anatomy of the eye, type and degree of glaucoma, and surgeon comfort and competence with individual procedures. Your surgeon will make a recommendation based upon full consideration of these and other factors.

Since their development over 60 years ago, lasers have revolutionized many fields, particularly medicine. Lasers allow us to easily and safely perform procedures which were once much more invasive, or not possible at all.

A laser is basically a very focused beam of light energy. The color of light emitted by a laser is determined by the type of material used to produce it. This material can be a gas, a liquid, a solid, or a semiconductor such as a diode. When the material inside the laser tube is energized, it produces light of a very specific wavelength, or color. In ophthalmology, lasers range in wavelength from infrared to ultraviolet. The wavelength determines how the laser will affect different cells and tissues within the body. The ability to control the exact amount of energy delivered by the laser makes it the perfect tool to perform precise, delicate surgery within the eye.

Laser Trabeculoplasty

Trabeculoplasty is a laser procedure performed for the treatment of open angle glaucoma. It is often recommended as an option when intraocular pressure (IOP) is not adequately controlled by medications alone, but can be performed as an initial means of lowering IOP in appropriate patients as well. A recent study, the LiGHT trial, concluded that laser trabeculoplasty is as safe and effective, and likely more cost-effective, than medications when used as a first-line treatment for glaucoma.

The procedure tends to reduce pressure by about 20 to 30 percent, or roughly the equivalent of one glaucoma medication. Trabeculoplasty demonstrates up to 80% success in lowering IOP, depending on certain characteristics of the patient being treated, such as number of glaucoma medications used, amount of pigment within the eye’s drainage canal, and type of glaucoma. The effects of this procedure are not permanent and tend to wear off after two to five years. Trabeculoplasty can be repeated when the treatment effect begins to fade, often with good pressure-lowering results.

Two forms of trabeculoplasty are available today. The original procedure, described in 1979, was performed using an argon laser, though currently a solid-state diode laser is often employed. These lasers produce light in the visible spectrum with a blue-green color. This type of treatment is often called “argon laser trabeculoplasty,” or ALT. ALT is a time-tested procedure which has been performed for over 40 years. The greatest drawback to ALT is that it can only be performed two to three times on an eye, as further treatments can actually cause injury.

A newer version of the procedure, known as “selective laser trabeculoplasty,” or SLT, achieves the same goal using a frequency-doubled neodymium:YAG laser, also producing light in the blue-green spectrum. Because the amount of energy delivered by this laser is less than that in ALT, the procedure can theoretically be repeated as many times as desired without risk of injury to the eye. Multiply repeated treatments performed years apart are often successful. Presently, we perform primarily the SLT procedure, based upon its better safety profile and ability to be repeated multiple times, as needed.

Trabeculoplasty will not cure glaucoma. Damage to the optic nerve cannot be reversed. The goal of trabeculoplasty, as with all treatments for glaucoma, is to lower intraocular pressure and prevent the further loss of vision. In some cases, glaucoma medications may be eliminated, however many patients will need to continue all pre-treatment eye drops to maintain adequately low IOP.

Trabeculoplasty is not 100% effective at lowering intraocular pressure. Results often vary depending upon the type of glaucoma, number and type of eye drops being taken, and other conditions affecting the eye. Your surgeon will discuss your specific situation and will provide appropriate guidance.

The Laser Trabeculoplasty Procedure

Laser trabeculoplasty is a short, in-office procedure. Most patients are able to drive to and from their appointment alone. Upon arrival, your vision and IOP will be tested. Your eye will then be numbed with an eyedrop, and additional drops may be given to help prevent post-operative pressure spikes. You will then be seated at the laser, which looks very similar to the microscope used to examine your eyes during a normal appointment. A contact lens will be placed on your eye to help focus the laser. A series of between 50 and 100 laser pulses will then be applied, during which time you will see flashes of light and may experience mild discomfort or burning. The contact lens will then be removed, and the gel used to help keep the contact lens in place will be washed away. Additional drops may be given, if necessary.

IOP elevations, or spikes, occur occasionally after the procedure and may need to be treated with extra medication. Therefore, you will be asked to wait or return approximately one hour after your treatment for a check of the pressure.

The full impact of SLT is typically seen in four to six weeks, and a follow-up appointment will be scheduled accordingly.

Mild discomfort, irritation, light sensitivity, and blurred vision are typical immediately after the procedure, and such mild symptoms may continue for two to four days afterwards. Post-operative anti-inflammatory medication (eye drops) will be provided for use for several days.

Complications from SLT are uncommon, with mild corneal or intraocular inflammation occurring infrequently, potentially requiring additional treatment. Complications causing loss of vision are exceedingly rare.

When medications or laser procedures fail to adequately control intraocular pressure (IOP), or if side effects prevent them continued use of medications, surgery becomes necessary to achieve the desired level of IOP. Surgery for glaucoma lowers IOP by either increasing the flow of fluid out of the eye or by decreasing the production of intraocular fluid.

When medications or laser procedures fail to adequately control intraocular pressure (IOP), or if side effects prevent the continued use of medications, surgery becomes necessary to achieve the desired level of IOP. Surgery for glaucoma lowers IOP by either increasing the flow of fluid out of the eye or by decreasing the production of intraocular fluid.

It must be remembered that the optic nerve damage and subsequent loss of vision caused by glaucoma cannot be reversed. Thus, the point of surgery is not to improve vision, but rather to prevent further vision loss. Currently there is no glaucoma treatment that can restore vision already lost to the disease. For this reason, early diagnosis and treatment are vital. We recommend reading the section about glaucoma before continuing here.

This article describes glaucoma drainage devices, a commonly performed surgical procedure used to treat many forms of glaucoma.

Introduction

Known as a “glaucoma drainage device,” “tube shunt,” “glaucoma valve,” or “Seton,” this procedure is often performed after other forms of glaucoma filtering surgery, most commonly trabeculectomy, have failed to adequately control intraocular pressure (IOP). Increasingly, however, it is being performed as an initial filtering procedure, and is usually the procedure of choice in cases considered high risk for trabeculectomy failure, such as neovascular or inflammatory glaucoma. A drainage device consists of a small tube which is inserted into the eye, usually into the anterior chamber near the edge of the cornea, and a plastic plate which is placed outside the eye beneath the conjunctiva, the clear membrane which covers the eye. The plate serves a bit like a reservoir, creating a space for aqueous humor to collect, much like the bleb in trabeculectomy.

For simplicity, think of glaucoma as being caused by a clogged drain. Aqueous humor is constantly being created but cannot escape quickly enough, building up pressure and damaging the optic nerve. The drainage device gives the fluid a low resistance means of escape, leading to lower, better controlled pressure. The fluid which leaves the eye via the tube drains into the space around the plate, beneath the conjunctiva, before being reabsorbed into the bloodstream.

A number of drainage devices are available from various manufacturers, varying in overall shape and size. The most significant difference between devices is the presence or absence of a flow-restricting valve. In some devices, a small valve serves to limit the amount of fluid that can flow out of the eye. The valve is meant to close if the IOP drops too low in order to avoid hypotony, or overly low pressure which can damage the eye. Drainage devices without valves must be temporarily obstructed at the time of implantation in order to avoid hypotony immediately following the procedure, as will be discussed in greater detail below. The type of device used is dependent upon the condition of the eye, particularly the level of IOP and severity of disease, as well as surgeon preference, with numerous factors taken into consideration.

Procedure in Detail

Drainage device surgery is generally performed as an outpatient procedure under local anesthesia with IV sedation- you will be awake but relaxed and will experience no discomfort. After the skin around the eye is cleansed, a surgical drape is placed over the eye to maintain sterility. A small device known as a lid speculum is placed in order to hold open the eyelids during the procedure. The eye is turned downward or upward depending upon where the surgical site will be located, exposing the conjunctiva and sclera. An incision is made in the conjunctiva, which is then carefully lifted and separated from the sclera, and the tissue is carefully dissected in order to create a pocket of space for the device’s plate to be placed. The device is then placed beneath the conjunctiva into the pocket and sutured to the sclera to maintain its position. If the device has no valve, the tube is tied tightly closed with a suture that will dissolve over a six to eight-week period. The tube is then cut to an appropriate length and a small incision is made into the eye, through which the tube is then inserted. The tube is also sutured to the sclera to prevent movement and may then be covered by graft material- usually donor human corneal tissue- which protects it from damage. Once all is in place the conjunctiva is sutured back into its normal position over the plate and tube.

Once surgery is completed, the eye is generally tightly patched and protected by a hard, plastic shield overnight. There is usually minor discomfort and itching. Significant pain is uncommon.

The Day after Surgery

The following morning you will come to the office for a post-operative checkup. The patch and shield will be removed, and the surgeon will check your vision, IOP, and the appearance of the eye, including the plate and tube. At this point instructions regarding acceptable levels of activity and use of postoperative eye drops, including steroids and antibiotics, will be given. It is very important that the drops be taken as prescribed in order that the surgery heals properly. The degree of allowable physical activity, including the ability to drive in the days following surgery, depends on each patient’s unique situation and must be judged individually. In general, strenuous activity, heavy lifting, and bending over should be avoided for the first one to two weeks.

The First Few Weeks after Surgery

Discomfort is generally mild in the first weeks after surgery. The eye may feel a bit sore, and typically there is a scratchy, foreign body sensation due to stitches. Vision is quite variable in these early days, ranging from almost normal to quite blurred. Don’t be alarmed if vision is poor initially, as acuity generally returns to preoperative levels after a few weeks, though may take longer and typically fluctuates quite a bit initially.

You will be monitored closely during the first one to two months following surgery, as this period of time is the most critical to achieving a successful outcome. Corticosteroid eye drops will be taken during this time on a tapering dose schedule and are critical to achieving a good outcome. Antibiotic drops will also be prescribed during the first week. Occasionally, other medications may also be required.

Valved devices will drain immediately, often leading to an initially low IOP that increases over the first few post-operative weeks. Not infrequently, these devices will experience a hypertensive, or high-pressure, phase, often 6-8 weeks after surgery. While additional glaucoma medication may be required to control IOP during this time, they can often be decreased as the pressure drops over the following months.

On the other hand, non-valved devices do not drain at the outset, as they have been tied closed with an absorbable suture. This allows the surrounding tissues time to heal before the suture dissolves and aqueous starts to drain. While non-valved implants may not control IOP as well as valved devices during the first six to eight weeks after surgery, studies show that they lead to lower pressures and somewhat higher success rates in the long term. As noted earlier, the choice of which type of device to implant is made based upon a number of factors taken into account by your surgeon.

Drainage device surgery may lead to a change in the eye’s refractive state, requiring a change in eyeglasses prescription. The eye is usually well healed and stable enough for this at about 8-10 weeks after surgery.

Months to Years after Surgery

Drainage device surgery is generally an effective procedure for IOP reduction, with a 60 to 80% chance of maintaining intraocular pressure at the desired level after one year. Unlike trabeculectomy, in which roughly half of patients need no additional IOP-lowering medication, drainage devices are more likely to require supplemental glaucoma medication to maintain adequate IOP levels. As the years pass it is not unusual for IOP to begin to increase, possibly necessitating the use of additional medications, or additional surgery. In approximately 20 to 40% of cases, surgery fails to adequately control the IOP beyond the first year or two. Additional surgery may then be performed to reach the desired level of pressure within the eye. A second drainage device might be implanted, or other options can be considered.

Patients who have undergone drainage device surgery have an increased lifetime risk of developing an infection inside the eye. Known as endophthalmitis, this kind of infection can seriously harm the eye and lead to loss of vision. The increased risk is due to the opening made in the eye; just as fluid can more easily escape the eye, bacteria can more easily enter. While this risk is generally low, anyone who has undergone drainage device surgery is advised to contact their ophthalmologist immediately if the operated eye ever becomes significantly red or painful, or if vision suddenly decreases. For this reason, the use of contact lenses after drainage device procedures is discouraged.

Risks of Surgery

All surgical procedures carry some risk of complications. Some risks are common to all procedures and patients, and others are more specific to certain types of surgeries or to patients with particular conditions. A thorough explanation of complications will be provided with a surgical consent, should you choose to have surgery, and your physician will review the specific issues you may face based upon your unique circumstances.

Complications

Complications of tube shunts can be divided into early (days to weeks after surgery) or late (months to years after surgery) problems. Some possible surgical complications are noted here:

Alternatives to Glaucoma Drainage Device Surgery

As with most diseases, there are a number of treatment options for glaucoma. As previously noted, surgery is usually considered when medications and laser trabeculoplasty have failed to adequately control IOP. Drainage device surgery, while a commonly performed surgical procedure for glaucoma, is not the only option available. Other surgical procedures may be considered based upon the type of glaucoma, condition of the eye, and level of IOP required. Your surgeon will discuss alternatives for your particular situation, as appropriate. Some of these procedures are detailed in other articles.