Who Benefits Most from Drainage Implants
Refractory glaucoma means glaucoma that has not responded well to other treatments. If you have tried multiple eye drops, had laser procedures, or gone through a trabeculectomy (a type of filtering surgery) without enough pressure reduction, you may benefit from a drainage implant. These devices are specifically designed for cases where standard approaches have fallen short.
Neovascular glaucoma happens when new, abnormal blood vessels grow over the part of the eye where fluid drains out. This type of glaucoma is often linked to diabetes or blockages in the blood vessels of the retina (the light-sensitive tissue at the back of the eye). Drainage implants can be especially helpful for this condition because the device bypasses the blocked drainage area entirely.
If you have had corneal transplants, retinal surgeries, or other procedures on your eye, the natural drainage pathways may have become scarred or damaged. Drainage implants work well in these situations because they create a completely new path for fluid to leave the eye. This makes them a strong choice for people with complex surgical histories.
Some people develop high eye pressure because of chronic inflammation inside the eye, a condition called uveitic glaucoma. Traditional filtering surgeries tend to scar more quickly in inflamed eyes, which can cause them to fail. Drainage implants often perform better in these cases because the device helps keep the drainage pathway open even when inflammation is present.
Children and younger adults who have congenital glaucoma (glaucoma present from birth) or juvenile glaucoma sometimes need drainage implants when other surgeries have not controlled their eye pressure. The implant can provide long-lasting pressure control during the many years of life ahead.
Who Is a Good Candidate for This Surgery
Most people who need a drainage implant are good candidates for the surgery. Your eye doctor will review your overall health to make sure you can safely undergo the procedure. You should be able to lie flat and still for the length of the surgery, which typically takes one to two hours. If you take blood-thinning medications, your doctor will discuss whether you need to adjust them before the procedure.
Your eye doctor will carefully examine your eyes to determine if a drainage implant is the right choice. They will look at several factors, including:
- Your current eye pressure and how well it is controlled
- The health of your optic nerve and how much damage has already occurred
- Whether you have enough healthy tissue on the surface of your eye to cover the implant
- Your history of previous eye surgeries and how your eye has healed in the past
- The type of glaucoma you have and how it has responded to other treatments
There are some situations where a drainage implant may not be the best option. Your doctor may suggest a different approach if you have certain conditions, such as:
- An active eye infection that needs to be treated first
- Severe scarring on the surface of the eye that would make it hard to place the device
- Very low eye pressure that does not need further reduction
- Certain conditions that affect the back of the eye and require a different surgical approach
Your surgeon at Washington Eye Institute will discuss all of these factors with you and help you understand whether a drainage implant is your best path forward.
Your complete treatment history plays a big role in deciding if you are a good candidate. Your doctor will want to know every medication you have used, every laser treatment you have had, and every surgery you have undergone for your glaucoma. This information helps your surgeon choose the right type of implant and plan the surgery to give you the best possible outcome.
How Glaucoma Drainage Implants Work
A glaucoma drainage implant is a small, lightweight device made of medical-grade materials that your body can tolerate well. The device has two main parts. The first part is a tiny tube, thinner than a strand of spaghetti, that is placed inside your eye. The second part is a small, flat plate that sits on the outside of your eye, underneath your eyelid where you cannot see or feel it. The tube connects to the plate, creating a pathway for fluid to flow out of the eye.
Your eye constantly makes a clear fluid called aqueous humor. This fluid nourishes the inside of your eye and then drains out through a natural meshwork. In glaucoma, this drainage system does not work properly, causing fluid to build up and pressure to rise. The drainage implant creates a new exit route for this fluid. The tube inside your eye collects the extra fluid and channels it to the plate on the outside of your eye. There, your body absorbs the fluid naturally into the surrounding tissue.
By giving fluid a new way to leave the eye, the implant reduces the amount of fluid building up inside. This lowers the pressure in your eye, which is the main goal of the surgery. Lower pressure helps protect your optic nerve from further damage and can slow or stop the progression of vision loss from glaucoma.
After surgery, a small, fluid-filled pocket called a bleb forms over the plate of the implant. This bleb sits underneath the thin tissue that covers the white of your eye, called the conjunctiva. The bleb acts as a reservoir where fluid collects before your body absorbs it. Your doctor will check the bleb at your follow-up visits to make sure it is working properly. In most cases, the bleb is hidden under your upper eyelid and is not visible to others.
Once in place, the drainage implant is designed to work for many years. The device does not have any moving parts, batteries, or components that wear out. Over time, your body forms a thin capsule of tissue around the plate, which actually helps regulate how much fluid drains. Your eye doctor will continue to monitor your eye pressure and the health of the implant at regular visits to make sure everything is functioning well.
Types of Drainage Implant Surgery
Some drainage implants have a built-in valve mechanism. This valve is designed to control the flow of fluid through the tube. It opens when the pressure inside your eye reaches a certain level and closes when the pressure drops low enough. The main advantage of a valved implant is that it begins working right away after surgery. This can help prevent the eye pressure from dropping too low in the early days after the procedure, a condition called hypotony.
Valved implants are often chosen when your surgeon wants immediate pressure control. They can be especially useful in cases of neovascular glaucoma or when eye pressure is very high and needs to come down quickly.
Non-valved drainage implants do not have a built-in flow-control mechanism. Instead, your surgeon ties a temporary stitch around the tube during surgery to block fluid flow at first. Over the following weeks, this stitch slowly dissolves, gradually allowing fluid to begin draining. During this waiting period, your surgeon may use other methods to manage your eye pressure, such as eye drops or small needle procedures in the office.
Non-valved implants tend to have a larger plate, which can create a bigger surface area for fluid absorption. Some studies suggest that non-valved implants may achieve slightly lower long-term eye pressures compared to valved devices. Your surgeon will help you understand which type is better for your specific situation.
Drainage implants come in different sizes. A single-plate implant has one drainage plate and is the most commonly used option. In some cases, when a larger drainage area is needed, your surgeon may recommend a double-plate implant. The double-plate version has two connected plates that are placed in different areas around the eye, providing more surface area for fluid absorption. This option may be considered for very advanced glaucoma or when a single-plate implant has not lowered the pressure enough.
There is no single drainage implant that works best for everyone. Your surgeon will consider several factors when choosing the right device for your eyes:
- The type and severity of your glaucoma
- Your history of previous eye surgeries
- How much space is available on the surface of your eye for the plate
- Whether you need immediate pressure reduction or can wait for a gradual effect
- Your overall eye health and any other conditions you may have
At Washington Eye Institute, your surgeon will explain the reasoning behind their recommendation so you can make an informed decision together.
What to Expect Before, During, and After Surgery
In the days and weeks before your drainage implant surgery, your eye doctor will give you specific instructions to follow. You may need to:
- Stop or adjust certain medications, especially blood thinners, as directed by your doctor
- Continue using your glaucoma eye drops until your surgeon tells you to stop
- Arrange for someone to drive you home after the procedure
- Avoid eating or drinking for several hours before surgery if you are receiving sedation
- Pick up any prescriptions your doctor has ordered for after the surgery
Your surgical team will also perform pre-operative measurements and tests to plan the best placement for your implant. This is a good time to ask any questions you may have about the surgery.
Glaucoma drainage implant surgery is performed in an operating room, usually as an outpatient procedure, meaning you go home the same day. The surgery typically takes one to two hours. Your surgeon will numb your eye so you do not feel pain, and most patients also receive light sedation to help them relax.
Your surgeon will make a small opening in the conjunctiva, the clear tissue covering the white of your eye. The plate of the implant is placed on the outside of your eye and secured with tiny stitches. Your surgeon then creates a small entry point into the front chamber of your eye and carefully inserts the tube. A small piece of donor tissue is placed over the tube where it enters the eye to protect it. The conjunctiva is closed with stitches that dissolve on their own over time.
The first week after surgery is an important time for healing. You can expect:
- Some redness, swelling, and mild discomfort in your eye, which is normal
- Blurry vision that gradually improves over days to weeks
- A need to use several different eye drops, including antibiotics to prevent infection and steroids to control inflammation
- An eye shield to wear while sleeping to protect your eye
- Restrictions on bending over, lifting heavy objects, and strenuous activity
Your surgeon will see you for a follow-up visit within the first day or two after surgery to check your eye pressure and make sure everything looks good.
Full recovery from drainage implant surgery takes several weeks to a few months. During this time, your eye pressure may go up and down as the bleb forms and matures. Your doctor will adjust your medications as needed.
- Weeks one through four: frequent follow-up visits, continued use of eye drops, and gradual return to light activities
- Weeks four through eight: the bleb is forming and your eye pressure is stabilizing, and your doctor may begin reducing some of your eye drop medications
- Months two through six: your eye continues to heal and adjust, and most patients see their eye pressure settle into a stable range during this period
It is very important to attend all of your follow-up appointments during this time. Your surgeon needs to monitor your healing closely and make any needed adjustments.
Like any surgery, drainage implant surgery carries some risks. Your surgeon will discuss these with you in detail before the procedure. Possible complications include:
- Eye pressure that is too low, especially in the early weeks after surgery
- Eye pressure that is still too high, which may require additional medications or procedures
- Infection, which is rare but requires prompt treatment
- Bleeding inside the eye
- The tube touching or rubbing against the cornea, which may need a minor adjustment
- Double vision, which usually improves on its own over time
- Movement or exposure of the implant, which may need a minor repair surgery
Most complications can be managed successfully when caught early. This is one of the reasons why regular follow-up care is so important after surgery.
For many patients, a drainage implant provides effective eye pressure control for years. Open-angle glaucoma accounts for 90% of all glaucoma cases in the United States (National Eye Institute, 2023), and drainage implants are an important tool in managing the most challenging of these cases. While the implant does not restore vision that has already been lost, it can help protect the vision you still have. Some patients may still need one or two eye drop medications along with their implant to keep their pressure at the right level. Regular check-ups with your eye doctor remain essential throughout your life to monitor the implant and your overall eye health.
Your Journey at Washington Eye Institute
Your care begins with a thorough evaluation by one of our glaucoma specialists. During this visit, your doctor will perform a complete eye exam, review your medical and surgical history, and discuss your treatment goals. Special tests may include:
- Tonometry, which measures the pressure inside your eye
- Gonioscopy, which lets your doctor see the drainage angle of your eye using a special lens
- Optical coherence tomography, a scan that takes detailed pictures of your optic nerve and retinal nerve fibers
- Visual field testing, which maps your peripheral vision to check for areas of vision loss
This evaluation gives your surgeon all the information needed to determine whether a drainage implant is right for you and to plan the best approach for your surgery.
After your evaluation, your surgeon will sit down with you and your family to discuss the findings. Together, you will create a treatment plan that fits your specific needs. Your surgeon will explain why a drainage implant is recommended for your situation, which type of implant is best suited for your eyes, and what to expect before, during, and after surgery. We believe you should feel confident and informed before moving forward with any surgical decision.
On the day of your surgery, our team will make sure you are comfortable and well-prepared. You will arrive at our surgical center, where a nurse will review your health information and get you ready for the procedure. Your surgeon will speak with you before the surgery to answer any last-minute questions. The surgery itself takes one to two hours, and you will be monitored carefully throughout.
After the procedure, you will rest in a recovery area for a short time. Once your surgical team is satisfied that everything looks good, you will be able to go home with your designated driver. You will receive detailed written instructions about your eye drops, activity restrictions, and when to come back for your first follow-up visit.
Your follow-up care is just as important as the surgery itself. At Washington Eye Institute, we schedule frequent visits in the weeks and months after your procedure to monitor your progress. During these visits, your doctor will check your eye pressure, examine the implant and bleb, adjust your eye drop medications as your eye heals, and look for any signs of complications. We are committed to supporting you through every step of your recovery.
Even after your eye has fully healed, regular glaucoma check-ups remain an important part of protecting your vision. Your doctor will continue to monitor your eye pressure, optic nerve health, and visual field over time. If adjustments are needed, whether to your medications, your implant, or your overall treatment plan, your team at Washington Eye Institute will be there to guide you. Our goal is to help you maintain the best possible vision and quality of life for years to come.
Questions and Answers About Glaucoma Drainage Implants
Most patients cannot feel the drainage implant after they have healed from surgery. The plate of the device sits underneath the conjunctiva and is usually hidden beneath your upper eyelid. In the early weeks after surgery, you may feel some awareness of the implant as your eye adjusts, but this sensation typically fades as healing progresses. If you ever notice persistent discomfort, irritation, or a feeling of something rubbing against your eyelid, let your doctor know right away so they can check the implant.
The timeline for seeing results depends on the type of implant used. With a valved implant, your eye pressure may begin to drop within the first few days after surgery. With a non-valved implant, it may take several weeks for the temporary stitch to dissolve and for fluid to begin draining through the tube. In either case, it often takes two to six months for your eye pressure to fully stabilize at its new, lower level. Your doctor will monitor your pressure closely during this time and adjust your treatment as needed.
Yes. Many patients find that they can reduce the number of eye drops they use after getting a drainage implant, but some people still need one or two medications to keep their eye pressure at a safe level. Your doctor will work with you to find the right combination of treatments. The goal is to lower your pressure enough to protect your optic nerve, and sometimes a combination of the implant plus eye drops achieves the best result.
After drainage implant surgery, you will need to take it easy for several weeks. Your doctor will ask you to avoid heavy lifting for at least two to four weeks, bending over at the waist, swimming or submerging your face in water until your doctor gives you the all-clear, rubbing or pressing on your eye, and vigorous exercise or contact sports for at least four to six weeks. Light activities such as walking, reading, and watching television are usually fine within a few days after surgery. Your surgeon will give you a specific list based on your individual procedure and healing progress.
In some cases, the drainage pathway created by the implant can become less effective over time. This usually happens because scar tissue forms around the plate, making it harder for fluid to be absorbed. If this occurs, your doctor has several options to help. These may include restarting or adjusting your eye drop medications, performing a minor office procedure to improve drainage around the plate, or in some cases, placing a second implant in a different area of the eye. Regular follow-up visits help your doctor catch any changes early so they can act quickly to keep your eye pressure under control.