Glaucoma Surgery

Introduction

If you have glaucoma and your eye doctor has raised the possibility of surgery, you are likely weighing what this means for your vision, your daily life, and the years ahead. You may have already tried eye drops, laser treatment, or both. Now the conversation has shifted to a surgical option, and that shift can feel like a big step.

The most important thing to understand at the outset is what glaucoma surgery is designed to do. It is performed to lower the pressure inside your eye and to protect the vision you still have. It is not a procedure that restores vision already lost to glaucoma. The optic nerve damage glaucoma causes is permanent, which is why surgeons and major eye-health societies focus so heavily on stopping further damage.

The good news is that the field of glaucoma surgery has changed substantially over the past two decades. Alongside long-established operations like trabeculectomy and tube-shunt implants, a newer family of procedures called MIGS (minimally invasive glaucoma surgery) has expanded the options available to many patients. Surgeons today often choose from a range of techniques, matched to the severity of the disease, the type of glaucoma, and the individual eye.

This article walks through what glaucoma surgery is, when it is considered, the main surgical approaches, how to prepare, what happens during and after the operation, and what life looks like afterwards. It is written for adults living with glaucoma and for parents of children with congenital or paediatric glaucoma, who face many of the same questions in a different clinical setting.

What Is Glaucoma Surgery?

Glaucoma is a group of eye diseases that damage the optic nerve, the bundle of nerve fibres that carries visual information from the retina (the light-sensitive tissue at the back of the eye) to the brain. In most forms of glaucoma, the damage is linked to elevated intraocular pressure (IOP) — the pressure of the fluid inside the eye.

The eye continuously produces a clear fluid called aqueous humour. This fluid nourishes the inner structures and then drains out through a meshwork in the drainage angle, where the iris meets the cornea. If this drainage is inefficient or blocked, fluid builds up and pressure rises. Over time, that pressure damages the delicate fibres of the optic nerve.

Glaucoma surgery refers to any operation that lowers eye pressure by improving the way fluid leaves the eye or, in some cases, by reducing how much fluid the eye produces. Depending on the technique, surgery may:

• Create a new pathway for fluid to drain out of the eye
• Open or enhance the eye’s natural drainage channels
• Insert a tiny device or tube that channels fluid out
• Treat the tissue that produces fluid, so less is made

The result, when successful, is a lower and more stable eye pressure, which protects the optic nerve from further damage. Glaucoma surgery is one part of a broader treatment journey that also includes medications, laser therapy, and lifelong monitoring.

Why Is Glaucoma Surgery Performed?

Major eye-care societies, including the American Academy of Ophthalmology (AAO) and the European Glaucoma Society, describe a general treatment ladder for glaucoma: medications and laser therapy are usually tried first, and surgery is considered when those measures are not enough to protect the optic nerve.

Doctors typically consider glaucoma surgery in situations such as:

• Pressure remains too high despite the maximum tolerated combination of eye drops
• The optic nerve is being damaged progressively, shown by changes on imaging tests or worsening visual field tests, even when measured pressure looks acceptable
• Drops are not tolerated — for example, because of severe side effects, allergies, or difficulty using them correctly
• Adherence is a challenge, such as in patients who find it difficult to use multiple drops every day for life
• Specific types of glaucoma that respond poorly to medication, such as some forms of angle-closure glaucoma, neovascular glaucoma, or congenital glaucoma
• Cataract surgery is planned, providing an opportunity to combine a MIGS procedure with cataract removal in the same operation

The decision to operate is individualised. It depends on how advanced the optic nerve damage is, how fast it is progressing, the type of glaucoma, the patient’s age, life expectancy, and other eye and general health factors. A glaucoma specialist usually weighs the risk of further vision loss without surgery against the risks of surgery itself.

Who Is a Candidate?

You may be considered a candidate for glaucoma surgery if some or all of the following apply:

• Your eye pressure has not reached a safe target level despite medical and laser treatment
• Your visual field tests show that vision loss is progressing
• Imaging of your optic nerve shows ongoing thinning of the nerve fibres
• You cannot use eye drops reliably because of side effects, physical difficulty, or other reasons
• You have a form of glaucoma that responds poorly to drops alone
• You are scheduled for cataract surgery and your surgeon recommends combining a MIGS procedure

Before surgery is offered, your ophthalmologist will assess factors including the severity of your glaucoma, your age and general health, the condition of your cornea and other parts of the eye, and your ability to attend the frequent follow-up appointments needed afterwards. Decisions about which type of surgery to recommend depend heavily on these factors.

Patients with very early or mild glaucoma well-controlled on drops are usually not candidates for traditional incisional surgery. At the other end of the spectrum, patients with very advanced damage or repeated failures of previous surgeries may need more complex procedures such as tube-shunt implants.

Alternatives to Surgery

Glaucoma surgery is one option in a wider toolkit. For most patients, doctors begin with non-surgical treatments and move to surgery only when these are insufficient. The main alternatives are:

Eye drops

Several classes of eye drops can lower intraocular pressure, either by reducing how much fluid the eye produces or by helping fluid drain more easily. Prostaglandin analogues, beta-blockers, alpha agonists, carbonic anhydrase inhibitors, and rho-kinase inhibitors are commonly used, sometimes in combination. Drops remain the first-line treatment for most types of glaucoma in current major guidelines.

Laser therapy

Laser procedures are office-based treatments that do not involve incisions. The most common are:

• Selective laser trabeculoplasty (SLT) — uses a low-energy laser to improve drainage through the eye’s natural meshwork. It is increasingly used as a first-line treatment for open-angle glaucoma, in line with recent guideline updates.
• Laser peripheral iridotomy (LPI) — creates a small opening in the iris to relieve or prevent angle-closure glaucoma.
• Laser cyclophotocoagulation — treats the ciliary body, the part of the eye that produces fluid, to reduce fluid production. Often used in more advanced cases or when other surgery is not suitable.

Continued medical management

For some patients, optimising drop regimens, addressing adherence challenges, or treating other contributing conditions (such as uncontrolled diabetes or sleep apnoea, which can interact with glaucoma management) is enough to delay or avoid surgery.

There is no single “glaucoma surgery.” The term covers several distinct operations, each with its own technique, advantages, and trade-offs. The choice depends on the type and severity of glaucoma, prior treatments, and individual eye anatomy.

Trabeculectomy

Trabeculectomy is one of the longest-established glaucoma operations and remains a standard option for moderate-to-advanced glaucoma.

The surgeon creates a small flap in the sclera (the white outer wall of the eye) and a tiny opening into the front chamber of the eye. Fluid then drains slowly out of this opening and collects under the conjunctiva (the thin clear tissue covering the white of the eye), forming a small blister-like reservoir called a bleb, usually hidden under the upper eyelid. From there, the fluid is gradually absorbed into surrounding tissues.

Trabeculectomy can produce significant pressure reduction and is often chosen when a low target pressure is needed. It requires careful long-term monitoring of the bleb and a relatively intensive schedule of post-operative visits, particularly in the first few months, to manage scarring and adjust healing.

Glaucoma Drainage Devices (Tube Shunts)

Glaucoma drainage devices, also called tube shunts or glaucoma drainage implants, are small medical devices that channel fluid out of the eye through a flexible tube connected to a plate stitched onto the eye wall under the conjunctiva.

Examples include the Ahmed, Baerveldt, and Molteno implants. Tube shunts are often chosen for:

• Eyes that have had unsuccessful trabeculectomy
• Complex or refractory glaucomas, including neovascular glaucoma and uveitic glaucoma
• Eyes with significant scarring of the conjunctiva

Tube shunts have a different risk and recovery profile from trabeculectomy and have been studied directly against it in major trials. Your surgeon will discuss which approach fits your specific eye.

Minimally Invasive Glaucoma Surgery (MIGS)

MIGS is a family of newer procedures that use very small incisions and tiny devices to lower eye pressure. They are generally designed to enhance the eye’s natural drainage pathways rather than create a large new external one. Examples include the iStent, Hydrus microstent, Xen gel stent, and procedures such as goniotomy, trabeculotomy, and canaloplasty performed through minimally invasive techniques.

MIGS procedures share several features:

• Smaller incisions and a generally shorter operating time
• Faster visual recovery compared with traditional surgery
• A favourable safety profile, with lower rates of some serious complications
• A more modest pressure-lowering effect than trabeculectomy or tube shunts
• Frequently combined with cataract surgery in the same operation

For these reasons, MIGS is often used in mild to moderate glaucoma, particularly when cataract surgery is already planned. The American Glaucoma Society and other major bodies have outlined the role of MIGS within the broader treatment ladder.

Cyclophotocoagulation

Cyclophotocoagulation uses a laser to reduce the activity of the ciliary body, the structure that produces aqueous fluid. Less fluid produced means lower pressure.

Traditionally used in advanced cases or eyes with poor visual potential, gentler versions such as micropulse transscleral cyclophotocoagulation are increasingly being considered in a broader range of patients. The role of these techniques continues to evolve as evidence accumulates.

Combined and Sequential Surgery

Some patients have more than one procedure either in a single operation (such as cataract surgery combined with a MIGS device) or in stages over time (for example, an initial MIGS procedure followed years later by a trabeculectomy if pressure rises again). Glaucoma is a chronic disease, and surgical planning often takes a long-term view.

Preparing for Glaucoma Surgery

Once you and your surgeon decide to proceed, preparation typically involves several steps in the weeks before the operation.

Pre-operative assessment

Your ophthalmologist will perform a detailed assessment, which usually includes:

• Tonometry to measure intraocular pressure
• Visual field testing to map any areas of vision loss
• Optical coherence tomography (OCT) of the optic nerve to measure the nerve fibre layer
• Gonioscopy to examine the drainage angle of the eye
• Examination of the cornea, lens, and retina to plan the safest approach

You will also have a general health review. Tell your team about all medications you take, including blood thinners and supplements, and any other medical conditions such as diabetes, high blood pressure, or breathing problems.

Medication adjustments

Your surgeon will give specific instructions about which eye drops to continue and which to stop before surgery. Some general medications, such as blood thinners, may need to be adjusted in consultation with the doctor who prescribed them. Do not stop or change medications on your own.

The day before and the day of surgery

You will usually be asked to:

• Avoid eating or drinking for a set number of hours before surgery if sedation or general anaesthesia is planned
• Wash your face and hair the day before, avoiding eye make-up on the day
• Arrange transportation home, since you will not be able to drive afterwards
• Bring a companion to help you home and during the first day

Glaucoma surgery is usually performed as a day-care procedure, meaning you go home the same day in most cases.

What Happens During Glaucoma Surgery

The exact steps depend on the type of surgery, but most procedures follow a similar overall pattern.

Anaesthesia

Most glaucoma operations are performed under local anaesthesia, often combined with light sedation to help you relax. The anaesthetic may be given as an injection around the eye or as drops and gel applied to the surface. You will be awake but should not feel pain. General anaesthesia is sometimes used, particularly for children or patients who cannot lie still.

During the operation

You will lie flat on an operating table, and a sterile drape will be placed around the eye. A small device will hold your eyelids open so you do not have to think about blinking. You may see lights and shapes and hear the surgical team, but you should not see the instruments clearly or feel sharp pain.

For a trabeculectomy, the surgeon creates the scleral flap and drainage opening, then carefully closes the conjunctiva over the new drainage site. Anti-scarring medication may be applied during the procedure to help the new pathway stay open.

For a tube shunt, the device’s plate is stitched to the eye wall, and the small tube is positioned inside the eye to allow fluid to drain.

For a MIGS procedure, a very small incision is made (often the same one used for cataract surgery), and a microscopic stent or device is placed in the drainage angle, or the natural drainage pathway is opened up using specialised instruments.

Most glaucoma operations take between 30 and 90 minutes, depending on the technique and complexity. MIGS combined with cataract surgery often adds only a few extra minutes to the cataract operation itself.

Immediately after surgery

Recovery and Healing

Recovery from glaucoma surgery is gradual and varies by procedure. MIGS procedures usually have a shorter and milder recovery than trabeculectomy or tube shunts.

The first days and weeks

In the early days, it is normal to experience:

• Blurred vision in the operated eye
• Mild discomfort, scratchiness, or a feeling that something is in the eye
• Redness and swelling
• Light sensitivity
• Tearing or watering

Eye drops — usually a combination of steroids and antibiotics — are central to recovery. They are typically used multiple times a day for several weeks and tapered slowly. Following the drop schedule precisely is important; missed doses can increase the risk of scarring or infection.

Follow-up visits

Frequent follow-up is one of the most important parts of glaucoma surgery recovery, particularly after trabeculectomy. Early visits may be scheduled within the first day or two, then weekly, then less often as healing stabilises. At these visits, your surgeon will check pressure, examine the surgical site, and may adjust drops or perform small in-office procedures such as removing or adjusting stitches.

What to avoid

For several weeks after surgery, you will generally be asked to:

• Avoid rubbing or pressing on the eye
• Avoid heavy lifting, straining, and strenuous exercise
• Avoid bending your head below your waist
• Avoid swimming pools, hot tubs, and exposing the eye to dirty water
• Wear the protective eye shield at night for a set period
• Use protective glasses outdoors, especially in dusty or bright environments

Your surgeon will give you specific timelines, since they vary by procedure.

Return to daily life

Many people can return to light activities such as reading, watching television, and walking within a few days, although vision may still be blurry. Driving is usually paused until your surgeon confirms it is safe. Return to work depends on the type of work and the type of surgery; office-based work is often possible within one to two weeks after MIGS but may take longer after trabeculectomy or tube shunts.

Risks and Complications

Glaucoma surgery, like any operation, carries risks. Modern techniques have improved safety, but it is important to understand what can happen so you know what to watch for. The specific risk profile depends on the type of surgery.

Possible complications include:

• Eye pressure that is too low (hypotony) — can cause blurred vision and, rarely, more serious changes inside the eye
• Eye pressure that remains too high, if the new drainage pathway does not work as well as hoped
• Bleeding inside the eye
• Infection, including a rare but serious infection inside the eye called endophthalmitis
• Scarring of the drainage site, which can reduce its function over time
• Cataract formation or progression, particularly after trabeculectomy
• Problems with the bleb after trabeculectomy, such as leakage or, less commonly, late bleb infections
• Tube-related problems after drainage implants, such as tube exposure, blockage, or contact with other eye structures
• Double vision or eyelid changes in some cases
• The need for additional surgery if pressure is not adequately controlled

Loss of vision after glaucoma surgery is uncommon but possible, particularly in eyes with already advanced disease. Your surgical team will discuss your individual risk in detail before you sign consent.

Call your eye doctor promptly if, in the weeks after surgery, you notice sudden worsening of vision, increasing pain, marked redness, discharge, or any sense that something is seriously wrong with the eye.

Life After Glaucoma Surgery

Glaucoma surgery is best understood as a step in the long-term management of a chronic disease, not as an endpoint. Even after successful surgery, glaucoma remains a condition that requires ongoing attention.

Vision after surgery

The aim of surgery is to protect remaining vision. It does not restore vision already lost to optic nerve damage. Many patients notice that, after a period of fluctuation, their vision returns close to where it was before surgery, sometimes a little better if cataract was treated at the same time, and is then more stable over the years.

Eye drops after surgery

Whether you can stop glaucoma drops depends on the type of surgery, how well it lowers your pressure, and your individual target pressure. Some patients are able to stop all drops; others continue to use one or more, but often fewer than before. This is a clinical judgment your ophthalmologist will make at follow-up.

Ongoing monitoring

Lifelong monitoring is standard after glaucoma surgery. Typical follow-up includes regular pressure checks, periodic visual field testing, and OCT imaging of the optic nerve to make sure the disease is stable. The interval between visits varies but is often every three to six months once things are settled.

Lifestyle considerations

Most people return to a full and normal life. General eye-healthy habits remain sensible:

• Attending all scheduled follow-up appointments
• Using prescribed drops consistently
• Protecting the eye from injury, especially during sport — protective eyewear is often recommended
• Managing other health conditions such as diabetes and high blood pressure, which affect overall eye health
• Reporting any sudden changes in vision promptly

Activities such as reading, screen use, and air travel are generally not restricted long-term, although your surgeon may set short-term limits during recovery.

If the first surgery is not enough

Sometimes a single operation does not bring the pressure down to the desired target, or the effect wears off over time as scarring develops. If this happens, options may include additional medications, a further laser treatment, or a second surgery using a different technique. Many patients with long-standing glaucoma have more than one procedure across their lifetime.

Glaucoma Surgery in Children

Glaucoma in children — including congenital glaucoma (present from birth or developing in the first years of life), juvenile open-angle glaucoma, and glaucoma secondary to other conditions — differs from adult glaucoma in important ways. Treatment is usually led by paediatric ophthalmologists or glaucoma specialists with experience in children.

Why surgery is often the main treatment

In many forms of paediatric glaucoma, particularly primary congenital glaucoma, the underlying problem is a developmental abnormality of the eye’s drainage angle. Eye drops alone are usually not enough to control pressure long-term, and surgery is often the first-line treatment recommended by paediatric glaucoma experts.

Surgical approaches in children

Procedures commonly considered include:

• Goniotomy — opening the drainage angle from inside the eye using a fine instrument
• Trabeculotomy — opening the drainage channels from outside the eye
• Trabeculectomy — usually with anti-scarring medication, in older children or when initial angle surgery is not enough
• Glaucoma drainage devices — for refractory cases or when other procedures have failed
• Cyclophotocoagulation — in selected situations

Practical considerations

Surgery in children is performed under general anaesthesia. Examinations under anaesthesia (EUA) are often used to monitor pressure and the optic nerve, since young children cannot cooperate with office-based testing. Visual development continues throughout childhood, so treating glaucoma promptly and managing other related issues such as refractive errors and amblyopia (“lazy eye”) is part of long-term care.

Parents should expect a long follow-up relationship with the paediatric eye team. With timely surgery and ongoing care, many children with glaucoma maintain useful vision into adulthood.

Frequently Asked Questions

Will glaucoma surgery restore vision I have already lost?

No. The optic nerve damage caused by glaucoma is permanent. Surgery is performed to lower eye pressure and protect the vision you still have, slowing or stopping further loss.

Is glaucoma surgery painful?

Most patients do not feel pain during the operation thanks to local anaesthesia, usually combined with sedation. Some discomfort, scratchiness, or mild aching is common in the first days after surgery and is generally manageable with the medications your team prescribes. Significant or worsening pain should always be reported.

How long does glaucoma surgery take?

Most procedures take between 30 and 90 minutes, depending on the technique. MIGS procedures are often shorter, particularly when combined with cataract surgery. You will usually be in the hospital or surgical centre for several hours overall, including preparation and recovery.

How long is the recovery?

Initial healing usually takes one to two weeks, with vision often blurry during this time. Eye pressure typically stabilises over the next several weeks, and full surgical evaluation is often complete by around three months. MIGS procedures generally have a faster recovery than trabeculectomy or tube shunts.

Will I still need to use eye drops after surgery?

It depends on the procedure, your individual response, and the target pressure your doctor is aiming for. Some patients are able to stop drops entirely; others continue to use one or more, often fewer than before. Your ophthalmologist will guide this based on follow-up pressure measurements.

Can both eyes be operated on at the same time?

For most incisional glaucoma surgeries, surgeons operate on one eye at a time, with the second eye scheduled later if needed. This reduces the risk of complications affecting both eyes at once and allows each eye to be assessed individually.

Can I fly after glaucoma surgery?

Air travel is generally avoided in the very early period after some types of glaucoma surgery, particularly if a gas bubble has been placed in the eye, which is uncommon in glaucoma surgery alone but can occur in combined procedures. Your surgeon will give you specific advice based on your operation.

What should prompt me to call my eye doctor urgently after surgery?

Contact your eye team promptly if you experience sudden worsening of vision, increasing pain, marked redness, discharge from the eye, flashes or a curtain across your vision, or a strong sense that something is wrong. Early review can prevent small problems from becoming serious.

Does glaucoma surgery cure glaucoma?

No. Glaucoma is a chronic disease, and surgery is one of the most effective ways to control eye pressure long-term, but it does not eliminate the underlying condition. Lifelong monitoring remains essential, even when surgery is highly successful.

Conclusion

Being told you may need glaucoma surgery is a significant moment in your treatment journey. It usually means that the simpler tools — drops and laser — are not enough to protect your optic nerve on their own, and that a more direct approach is needed to keep your vision as stable as possible for as long as possible.

Modern glaucoma surgery offers a range of approaches, from long-established operations like trabeculectomy and tube-shunt implants to newer minimally invasive techniques. Each has its place, and the right choice depends on the type and stage of your glaucoma, the structure of your eye, your overall health, and your previous treatments. The decision is made together with a glaucoma specialist, based on a careful assessment of how much risk to your vision exists if surgery is delayed versus the risks of surgery itself.

After surgery, the most important contributors to a good long-term outcome are consistent use of any prescribed drops, attendance at follow-up visits, and prompt reporting of unusual symptoms. Glaucoma remains a lifelong condition, but with timely surgery and steady follow-up, many patients preserve useful vision for many years.