Selective Laser Trabeculoplasty (SLT) is a laser treatment used to lower intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension. It helps improve drainage of fluid from the eye, reducing pressure and preventing further damage to the optic nerve. SLT has been shown in high quality studies to be better than eye drops as an initial treatment for glaucoma. It is now recommended by national guidelines as the first treatment for most patients with ocular hypertension or glaucoma.
In addition to be recommended as initial treatment, SLT may be recommended if:
Eye pressure remains high despite using eye drops or other treatments.
You have difficulty tolerating glaucoma medications.
Additional pressure reduction is needed to prevent glaucoma progression.
SLT uses a low-energy laser to target specific cells in the eye’s drainage system (the trabecular meshwork). This stimulates natural healing responses, improving fluid outflow and lowering eye pressure. The laser treatment is selective and does not damage surrounding tissues, making it a safe and repeatable procedure.
Before Treatment: Numbing eye drops will be applied to ensure comfort.
During Treatment: A special contact lens is placed on the eye, and short laser pulses are applied to the trabecular meshwork. The procedure is painless and typically takes 5-10 minutes.
After Treatment: Normally no extra eye drops are needed. You can resume normal activities immediately, but follow-up visits will be scheduled to monitor your eye pressure.
Non-invasive
Quick and Safe: A short outpatient procedure with minimal discomfort.
Long-Lasting Effects: Can lower eye pressure for several years.
Repeatable: Can be repeated if needed.
Better than eye drops: patients treated with SLT first lost less visual field and required fewer glaucoma operations than those treated with eye drops.
What is the evidence?
The LIGHT (Laser in Glaucoma and Ocular Hypertension) study was a large clinical trial that compared SLT with traditional eye drop treatments as an initial treatment. The results showed that:
74.2% of patients treated with SLT did not require eye drops for at least three years after the procedure.
SLT was as effective as eye drops in controlling eye pressure.
Patients who underwent SLT were more likely to maintain a good eye pressure without additional treatment compared to those on eye drops.
SLT had fewer side effects and reduced dependence on daily medications.
SLT was a cost-effective alternative for long-term glaucoma management.
The LIGHT study showed SLT is a safe and effective first-line treatment for glaucoma and ocular hypertension and SLT is now recommended by The National Institute for Health and Care Excellence (NICE).
SLT is generally safe, but some potential side effects include:
Temporary eye redness or discomfort.
Mild inflammation (some patients require a short course of anti-inflammatory eye drop).
A slight increase in eye pressure (rare and usually temporary).
The effect may wear off over time, requiring repeat treatment or additional therapy.
You will need a follow-up appointment within 5-6 weeks to assess your eye pressure.
Continue using any prescribed medications unless advised otherwise.
You can resume all normal activities immediately after the procedure, though it is sensible not to drive home after laser as vision will likely be slightly blurred for a short duration.
Inside the eye, a clear fluid called aqueous humour is continuously produced and drained away through the drainage angle between the iris (the coloured part of the eye) and the cornea (the clear front window of the eye).
In some people, this angle becomes very narrow or blocked. This is known as angle closure.
When the drainage angle closes:
Eye pressure can rise suddenly or gradually
The optic nerve may become damaged
Permanent sight loss from glaucoma can occur
Angle closure may occur suddenly (acute angle closure) or develop slowly over time.
Dr Tatham may recommend laser iridotomy if:
You have narrow drainage angles
You are at risk of angle closure glaucoma
You have had an acute angle closure attack
Eye pressure is elevated due to angle closure
One eye has already experienced angle closure
Laser iridotomy helps reduce the risk of future angle closure and sight loss.
Laser peripheral iridotomy (LPI) is a commonly performed outpatient laser procedure.
A laser is used to create a tiny opening in the outer edge of the iris. This opening allows fluid to flow more freely within the eye and helps open the drainage angle.
The procedure usually takes around 10–15 minutes per eye.
Before treatment:
Your vision and eye pressure will be checked
Eye drops will be placed in the eye to constrict the pupil
Anaesthetic drops will numb the surface of the eye
You should continue your usual medications unless advised otherwise.
Because your vision may be temporarily blurred afterwards, it is advisable not to drive yourself home.
You will sit at a laser machine similar to the microscope used during routine eye examinations.
During the procedure:
A small contact lens is placed on the eye
The laser is focused on the iris
Several laser pulses are delivered to create a small opening
You may notice:
Bright flashes of light
A clicking sound
Mild discomfort or a brief sharp sensation
Most patients tolerate the procedure well.
After treatment:
Your eye pressure is usually checked within 30–60 minutes
Anti-inflammatory eye drops are commonly prescribed for several days
Vision may be blurred for a few hours
You can usually return to normal activities the following day.
Common temporary symptoms include:
Mild ache or headache
Light sensitivity
Redness
Blurred vision
These symptoms generally settle within a few days.
The main benefits are:
Reducing the risk of acute angle closure
Lowering eye pressure in some patients
Protecting the optic nerve from glaucoma damage
Helping preserve vision
Some patients may still require glaucoma drops, cataract surgery, or additional treatment afterwards.
Laser iridotomy is generally very safe. Serious complications are uncommon, but all procedures carry some risk.
Temporary blurred vision
Occurs in approximately 10–20% of patients and usually settles within hours to days.
Mild inflammation
A small amount of inflammation inside the eye is common after treatment and occurs in up to 30% of patients. This is usually controlled with anti-inflammatory drops.
Temporary rise in eye pressure
A short-term increase in eye pressure occurs in approximately 5–10% of patients. This is usually mild and temporary, but occasionally requires additional drops or treatment.
Small bleed from the iris
Minor bleeding can occur in around 5% of procedures and almost always stops quickly without long-term problems.
Light glare or visual symptoms
Around 2–10% of patients notice glare, lines, halos, or awareness of the iridotomy opening. Persistent troublesome symptoms are uncommon.
Less common complications
Closure of the iridotomy opening
The opening may partially close in approximately 1–5% of patients, occasionally requiring repeat laser treatment.
Corneal swelling or damage
Temporary corneal irritation or swelling occurs in fewer than 1% of cases and usually resolves.
Cataract progression
There is a small risk that cataract formation may accelerate over time, although this is uncommon.
These complications are very uncommon (generally less than 1 in 1,000 cases):
Significant bleeding
Persistent high eye pressure
Retinal problems
Permanent reduction in vision
Severe inflammation or infection
Permanent severe sight loss from laser iridotomy is extremely rare.
Please contact the clinic urgently or seek emergency eye care if you develop:
Severe or worsening eye pain
Sudden deterioration in vision
Increasing redness
Nausea or vomiting associated with eye pain
Flashes, floaters, or a dark curtain in the vision
You will usually require follow-up appointments to:
Check the iridotomy remains open
Monitor eye pressure
Assess the drainage angle
Monitor for glaucoma
Continue all prescribed eye drops unless advised otherwise.
Will this improve my eyesight?
The purpose of laser iridotomy is primarily to prevent glaucoma and protect vision. It may not improve existing eyesight.
Will I still need glasses?
Yes. The procedure does not remove the need for glasses.
Can angle closure still happen afterwards?
Laser iridotomy substantially reduces the risk of angle closure, but some patients may continue to have narrow angles or require further treatment.
Will I need additional treatment?
Some patients still require:
Glaucoma eye drops
Cataract surgery
Further laser treatment
You have been advised to consider a trabeculectomy to help manage your glaucoma. Glaucoma is usually associated with increased pressure inside the eye, which can damage the optic nerve and affect your vision over time.
A trabeculectomy is an operation designed to lower this pressure. It works by allowing fluid from inside your eye (called aqueous humour) to drain more effectively. This fluid is different from tears and is naturally produced inside the eye.
During the procedure, Dr Tatham creates a small drainage channel in the wall of the eye. This allows fluid to pass into a small reservoir under the surface of the eye, known as a bleb, which is usually hidden beneath your upper eyelid. By improving drainage, the pressure inside your eye is reduced, helping to protect your vision.
It is important to understand that this surgery is aimed at preserving sight—it cannot restore vision that has already been lost.
Dr Tatham may recommend trabeculectomy if your eye pressure is not adequately controlled with drops or laser treatment, or if there are concerns that your glaucoma is progressing.
Trabeculectomy is one of the most effective treatments available for lowering eye pressure and reducing the risk of further vision loss.
The surgery typically takes around 45 to 60 minutes. It is most commonly performed under local anaesthetic, meaning your eye will be numb but you will remain awake.
If you feel anxious about being awake during the procedure, sedation can be arranged to help you relax—this is something you can discuss beforehand.
You will not be able to see the operation itself, as a sterile drape is placed over you. You may be aware of movement or gentle pressure around the eye, but you should not feel pain. If at any point you are uncomfortable, the anaesthetic can be topped up.
During surgery, a small flap is created in the white of the eye (the sclera), and a controlled drainage opening is made. Very fine stitches are used to regulate how much fluid drains out.
To improve the success of the operation, medications such as Mitomycin C may be applied to reduce scarring. This helps keep the drainage channel working over the long term.
After surgery, your eye will usually be covered with a pad or shield. Most patients go home the same day or the following day.
Your eye may look red and feel uncomfortable at first, and your vision is often blurred. This is normal. Vision is usually most blurred in the first one to two weeks and then gradually improves, although it can take two to three months to fully settle.
You will begin using eye drops the day after surgery. These typically include antibiotic drops to prevent infection and steroid drops to reduce inflammation. These drops are very important and may need to be used for several weeks or months, with adjustments made during your follow-up visits.
Glaucoma drops for the operated eye are usually stopped after surgery unless you are told otherwise.
Trabeculectomy requires careful follow-up to ensure the best outcome.
You will be seen regularly in clinic, especially during the first few weeks. Early on, visits are often weekly, and sometimes more frequent if needed. During these visits, Dr Tatham may adjust stitches, gently massage the eye, or occasionally perform minor procedures (such as removing stitches or “needling” the drainage area) to optimise how the surgery is working.
Your surgical fee includes all follow-up visits during the first 6 weeks after your operation.
Healing takes time, and it is important to take things gently in the early weeks.
Your eye may feel sore, partly due to the surgery and partly due to the stitches. These stitches are usually removed in clinic after a few weeks, which often improves comfort.
You will be asked to wear an eye shield at night for a short period to protect the eye while sleeping.
Most people can return to light daily activities fairly quickly, such as reading or watching television. However, you should avoid strenuous activity—such as heavy lifting, swimming, jogging, or contact sports—for several weeks.
Bending forward or positions where your head is down (such as in yoga) should also be avoided early on, as this can be uncomfortable.
Returning to work depends on your job. Office-based work may be possible after around two weeks, while more physical jobs may require longer.
After surgery, the eye is often red and slightly swollen. The eyelid may droop a little initially. This usually improves over time.
The drainage bleb created during surgery is usually not noticeable, although you may be able to see it if you lift your upper eyelid. Most people are not aware of it in everyday life.
Trabeculectomy is generally very effective at lowering eye pressure. Many patients achieve good pressure control without needing further glaucoma drops, although some may still require medication.
Long-term studies suggest that the majority of trabeculectomies continue to work well for many years, although the outcome varies between individuals. A small number of patients may need further surgery in the future.
As with any surgery, there are risks, although serious complications are uncommon.
In the early period after surgery, the main concern is that the eye pressure may become too low or too high. Occasionally, this may require further treatment or a return to theatre to adjust the surgery.
There is also a small risk of infection or bleeding. Although rare, infection can occur even years later, so it is important to seek urgent medical attention if your eye becomes red, painful, or sticky.
Other longer-term issues can include:
Development or progression of cataract
Changes in your glasses prescription
Discomfort or dryness from the drainage bleb
Most complications can be managed effectively, especially if detected early.
You should contact the clinic immediately if you experience:
Increasing pain
Sudden worsening of vision
Significant redness
Discharge from the eye
Prompt assessment is important to prevent complications.
Trabeculectomy is a well-established and effective procedure for controlling glaucoma and protecting vision. It does, however, require commitment to follow-up and careful aftercare in the early stages.
Dr Tatham and the team will guide you through every step of the process. If you feel anxious about the procedure, options such as sedation are available, and any concerns can be discussed in advance.
If you have any questions at any stage, please do not hesitate to ask.
Click here for a more detailed PDF version of trabeculectomy information.
The PRESERFLO™ MicroShunt is a small, flexible tube measuring approximately 8.5 millimeters in length. It is implanted into the eye to help lower intraocular pressure (IOP) in patients with glaucoma. The device is made from a synthetic material called SIBS (styrene-block-isobutylene-block-styrene), which is biocompatible and designed to remain stable over time. It is non-metallic, so it will not trigger airport scanners and is safe for MRI or CT scans.
In glaucoma, increased IOP can damage the optic nerve, leading to vision loss. The PRESERFLO™ MicroShunt creates a new drainage pathway for the aqueous humor (the fluid inside the eye), allowing it to flow out of the eye and thereby reducing IOP. This helps prevent further damage to the optic nerve.
The PRESERFLO™ MicroShunt is intended for patients with primary open-angle glaucoma where IOP remains uncontrollable despite maximum tolerated medical therapy, or where glaucoma progression warrants surgical intervention.
Effective IOP Reduction: Studies have shown that the PRESERFLO™ MicroShunt can significantly lower IOP.
Reduced Medication Dependence: Many patients experience a decrease in the need for glaucoma medications after the procedure.
Minimally Invasive: The procedure is less invasive compared to traditional glaucoma surgeries, potentially resulting in fewer complications and a quicker recovery.
As with any surgical procedure, there are potential risks, including:
Vision Changes: Temporary or, in rare cases, permanent vision loss.
Infection: Risk of infection inside the eye.
Bleeding: Bleeding inside the eye during or after surgery.
Hypotony: Excessively low IOP.
Device Exposure: Exposure or movement of the implant.
Alternative treatments include medications (eye drops), laser therapy, or other surgical procedures like trabeculectomy.
Before the Procedure
Medications: Continue using your prescribed eye drops unless advised otherwise.
After the Procedure
Medications: Use prescribed eye drops to prevent infection and control inflammation.
Activities: Avoid rubbing your eye and refrain from strenuous activities until your doctor advises otherwise.
Follow-Up: Attend all follow-up appointments to monitor your recovery and IOP levels.
You have been advised to consider aqueous shunt surgery to help manage your glaucoma. Glaucoma is a condition where damage to the optic nerve—often related to raised pressure inside the eye—can lead to gradual loss of vision.
Inside your eye, a clear fluid called aqueous humour is constantly produced. This fluid is different from tears and is responsible for maintaining the eye’s pressure. In glaucoma, this fluid does not drain properly, leading to increased pressure.
An aqueous shunt (also called a tube implant or drainage device) is designed to lower this pressure by creating a new drainage pathway. The device consists of a very fine tube connected to a small plate. The tube drains fluid from inside the eye to the plate, which sits on the surface of the eye under the eyelid. The fluid then collects in a small reservoir (bleb) and is gradually absorbed by the body.
This surgery helps protect your vision by reducing pressure, but it cannot restore vision that has already been lost.
Dr Tatham may recommend an aqueous shunt if your eye pressure remains too high despite treatment with drops, laser, or previous surgery.
Tube surgery is often used in more complex or advanced glaucoma, or when other treatments are less likely to succeed. It is a well-established and effective way of lowering eye pressure.
There are several types of aqueous shunt, and they all work in a similar way, although there are some differences in design and how they control pressure.
Commonly used devices include the Ahmed valve, which has a built-in mechanism to reduce the risk of very low pressure in the early period after surgery, and non-valved devices such as the Baerveldt tube and the Paul tube. These non-valved tubes do not contain a valve, so they are temporarily restricted with a fine stitch at the time of surgery to control the flow of fluid while the eye heals.
Dr Tatham will choose the most appropriate type of shunt for your individual circumstances and discuss this with you.
Aqueous shunt surgery usually takes between one and two hours.
It is often performed under general anaesthetic, although in some cases it can be done under local anaesthetic. If you are awake during the procedure, sedation can be arranged to help you feel more relaxed.
During the operation, a small tube is inserted into the eye and connected to a plate that sits on the surface of the eye, under the conjunctiva (the thin skin covering the eye). The tube is extremely small and cannot be seen without magnification.
A patch made from donor tissue is usually placed over the tube to protect it and reduce the risk of exposure. This tissue is carefully screened and is used only as reinforcement—it is not a transplant.
Medication such as Mitomycin C may be used during surgery to reduce scarring and improve long-term success.
After surgery, your eye is likely to be red and slightly swollen, and the eyelid may droop temporarily. This usually improves over several weeks.
The shunt itself is not normally visible. The plate and drainage area are positioned under the eyelid, so they cannot usually be seen in everyday life. Occasionally, parts of the device may be visible if you look in certain directions or lift your eyelid.
Most people are not aware of the tube once the eye has healed.
Your eye will usually be covered with a pad or shield immediately after surgery. This is typically removed the following day at your first check-up.
Most patients go home the same day or the next day. You should arrange for someone to accompany you home.
Your vision will be blurred at first, and the eye may feel uncomfortable. This is normal. Vision typically improves gradually over several weeks, although it can take two to three months to fully stabilise.
You will start eye drops the day after surgery. These usually include:
Antibiotic drops to prevent infection
Steroid drops to reduce inflammation
The steroid drops are often used frequently at first and then gradually reduced over time. These drops are essential for healing and must not be stopped or altered without advice.
Glaucoma medications for the operated eye are often stopped after surgery, although you may still need drops in the longer term. Drops for the other eye should be continued unless advised otherwise.
Careful follow-up is a key part of successful tube surgery.
You will be seen regularly in clinic, often weekly in the first month. These visits allow Dr Tatham to monitor your eye pressure and ensure the shunt is working properly.
In some cases, additional procedures may be needed to adjust how the tube functions. For example, a stitch controlling the tube may be released with a laser after a few weeks, or removed later to allow full drainage.
Occasionally, if the pressure is too low or too high, further treatment or a small operation may be needed.
Your surgical fee includes all follow-up visits during the first 6 weeks after your operation.
Recovery takes time, and it is important to allow your eye to heal properly.
You can safely read and watch television, but you should avoid strenuous activities such as heavy lifting, swimming, jogging, or contact sports in the early weeks.
You should also avoid bending forward or positions where your head is down, as this can be uncomfortable while the eye is healing.
Most people can return to office-based work after around two weeks, although more physically demanding work may require a longer break.
It is usually possible to resume contact lens wear after about four weeks, although this depends on how the eye heals.
Aqueous shunt surgery is effective in lowering eye pressure in the majority of patients. Studies suggest success rates of around 70–80% at five years.
Some patients achieve good pressure control without further medication, while others may still need a small number of drops.
Many shunts continue to function well long term, although additional treatment may sometimes be required.
Serious complications are uncommon, but as with any surgery, there are risks.
In the early period, the main concern is that the eye pressure may become too low or too high. Very low pressure can occasionally lead to bleeding inside the eye, although this is rare.
There is also a small risk of infection, both shortly after surgery and in the long term. Any redness, pain, or discharge should be assessed urgently.
Other possible complications include:
Blockage of the tube
Movement or exposure of the tube
Irritation or damage to the cornea
Need for further surgery
In a small number of cases, additional procedures are required to adjust the tube or manage pressure.
You should contact the clinic immediately if you notice:
Increasing pain
Sudden worsening of vision
Significant redness
Discharge from the eye
Prompt treatment is important to prevent complications.
Aqueous shunt surgery is a well-established treatment for glaucoma, particularly in more complex cases. It offers an effective way to lower eye pressure and protect your vision over the long term.
Recovery requires patience and regular follow-up, but Dr Tatham and the team will guide you through each stage of the process.
If you feel anxious about surgery, sedation can be arranged, and any concerns can be discussed in advance.
If you have any questions at any stage, please do not hesitate to ask.
Please click here for a detailed PDF leaflet about aqueous shunts.
MIGS is a group of safer "keyhole" eye surgeries designed for to lower eye pressure with fewer complications than traditional surgery. They use microscopic equipment through tiny incisions to improve natural fluid drainage, often combined with cataract surgery to reduce reliance on daily eye drops. MIGS include iStent and Hydrus. The UK and Eire Glaucoma Society (UKEGS) recommend that MIGS are considered for most patients with glaucoma undergoing cataract surgery.
The iStent infinite® is a small medical device used to help manage open-angle glaucoma, a condition that can gradually damage your vision. The treatment involves placing three very small stents, which are tiny tube-like devices, inside the eye to improve fluid drainage and reduce pressure.
The iStent infinite device contains three tiny titanium stents that are implanted inside the eye during surgery. These stents create new pathways that allow fluid to drain more effectively from the eye. By improving drainage, the device helps to lower eye pressure. Once implanted, the stents are not visible and cannot be felt.
On the day of surgery, you will receive eye drops and possibly medication to help you relax. Your eye will be numbed so that you do not feel pain during the procedure. Dr Tatham will make a small incision in the eye and use a special instrument to implant the three stents. The operation is typically combined with cataract surgery but can be done standalone.
After the procedure, a protective shield may be placed over your eye. You will spend a short time recovering before going home the same day. You will need someone to drive you home.
The main benefit of the iStent infinite is lowering eye pressure and reduce dependency on eye drops. In a clinical study, about three-quarters of patients experienced a reduction of 20 percent or more in eye pressure after one year, while using the same or fewer eye drops.
As with any eye surgery, there are risks, including infection, bleeding, inflammation, swelling, changes in vision, or increased eye pressure. There are also risks specific to the iStent infinite. In some cases, the stents may not be placed correctly or may become blocked over time. Additional treatment, such as medication or further surgery, may be needed. Other possible complications include inflammation, tissue injury, or progression of glaucoma. Overall the risks of istent combined with cataract surgery are similar to the risks of cataract surgery alone.
After your procedure, you will receive an implant identification card. This card contains important information about your device and should be kept safe. You should show this card to any healthcare provider you see in the future. It is usually safe to have an MRI scan ater istent. Made of non-magnetic titanium, they do not cause significant heating, displacement, or image artifacts in standard, safe MR environments (e.g., 3 Tesla). It is recommended to inform your doctor about the implant.
The Hydrus Microstent is a small, flexible device designed to help reduce eye pressure in patients with mild to moderate open-angle glaucoma. It is made from a biocompatible alloy (nitinol) and is implanted into the eye’s Schlemm’s canal to improve fluid drainage and lower intraocular pressure (IOP).
The Hydrus Microstent is typically recommended for patients who:
Have mild to moderate open-angle glaucoma
Need additional pressure reduction despite using glaucoma medications
Are undergoing cataract surgery, as the stent is often implanted during the same procedure
Glaucoma is caused by a buildup of fluid in the eye, leading to increased intraocular pressure (IOP). The Hydrus Microstent enhances the eye’s natural drainage system by:
Expanding the Schlemm’s canal to increase fluid outflow
Bypassing resistance in the eye’s drainage pathway
Reducing dependency on glaucoma medications
The stent is implanted during cataract surgery or as a standalone procedure
It is inserted through a tiny incision in the cornea
The procedure is quick, typically taking 10-15 minutes
Recovery is usually fast, with minimal discomfort
✔ Reduces eye pressure and slows glaucoma progression
✔ Minimally invasive with a quick recovery time
✔ May reduce or eliminate the need for glaucoma eye drops
✔ Implanted during cataract surgery, avoiding additional surgeries
While the procedure is generally safe, some risks include:
Temporary eye irritation or redness
Mild inflammation or discomfort
Increased eye pressure (rare and usually temporary)
Possible need for additional glaucoma treatments
Your doctor will monitor your progress and address any complications if they arise.
Use prescribed eye drops to aid healing and reduce inflammation
Avoid rubbing your eyes and follow post-operative care instructions
Attend all scheduled follow-up appointments to monitor eye pressure
Contact your doctor if you experience severe pain, vision changes, or swelling
1. Will I still need glaucoma medications after the procedure?
Some patients may reduce or stop using medications, but others might still require them.
2. How long does the stent last?
The stent is designed to remain in place permanently and continue working indefinitely.
3. Can the Hydrus Microstent be removed?
It is not usually removed, as it is designed to be a permanent implant.
4. How soon can I resume normal activities?
Most patients can return to normal activities within 3 weeks.