Canaloplasty for Glaucoma
What Canaloplasty Is and How It Treats Glaucoma
Your eye constantly produces a clear fluid called aqueous humor that normally drains through a tiny canal called Schlemm's canal. In glaucoma, increased resistance occurs primarily at the trabecular meshwork and the inner wall of Schlemm's canal, and the canal itself may collapse or narrow. Blockages in the collector channels beyond the canal can also limit drainage. When fluid cannot exit efficiently, pressure builds up inside your eye.
Canaloplasty works by threading a tiny catheter around the entire canal to stretch it open and dilate the collector channel openings. We also place a permanent suture inside the canal that acts like a scaffold to help keep the canal open over time. This enhances your eye's conventional outflow pathway and lowers eye pressure, though it does not restore completely normal drainage in every eye. The result depends on your individual anatomy and how your eye heals after surgery.
Ab-externo canaloplasty is the traditional approach where we make a small flap in the white part of your eye to reach the drainage canal from the outside. This method allows us to thread a catheter all the way around the canal and place a tensioning suture. Ab-interno canaloplasty uses a smaller, inside-the-eye approach through the cornea, which may be less invasive and typically does not include a tensioning suture.
Ab-interno canaloplasty is often classified as an angle-based minimally invasive glaucoma surgery, or MIGS. Some ab-interno systems perform viscodilation of the canal with or without additional trabeculotomy, depending on the device and surgeon preference. Our ophthalmologist will choose the best approach based on your specific type of glaucoma, how advanced it is, and whether we are combining the surgery with cataract removal.
We may recommend canaloplasty if your glaucoma medications are not lowering your eye pressure enough or if you are experiencing side effects from multiple drops. This procedure is often a good option when you need more pressure reduction than laser treatment can provide but want to avoid the higher complication rates of traditional filtering surgeries. Canaloplasty works especially well for primary open-angle glaucoma and some cases of secondary glaucoma when your drainage angle is open on examination and distal outflow is relatively intact.
- Your eye pressure remains too high despite maximum medical therapy
- You cannot tolerate or afford your glaucoma medications
- You need surgery but want to preserve your eye's natural anatomy
- You wish to avoid the long-term risks of trabeculectomy or tube implants
Canaloplasty is generally not suitable if you have certain secondary glaucomas such as neovascular glaucoma, active uveitic glaucoma, or significant angle scarring. Severe distal outflow compromise also makes this procedure less likely to succeed.
Trabeculectomy and tube shunt surgeries are traditional filtering procedures that create a new pathway for fluid to leave your eye by making an opening under the eyelid. These procedures often achieve lower pressures than canaloplasty but carry higher risks of infection, scarring, and vision-threatening complications. Canaloplasty typically has fewer serious complications because it preserves your eye's natural structure.
However, canaloplasty may not lower pressure as much as these filtration surgeries. We generally consider canaloplasty for mild to moderate glaucoma when you need better control than medications alone but do not require the aggressive pressure reduction that trabeculectomy provides. For very advanced glaucoma or when a very low target pressure is required, trabeculectomy and tube shunts remain appropriate, standard treatment options and may be recommended earlier depending on your disease severity and rate of progression.
Other surgical alternatives include laser trabeculoplasty, angle-based MIGS such as trabecular bypass stents, goniotomy, trabeculotomy, and other viscodilation systems. Some patients may benefit from cyclophotocoagulation or nonpenetrating filtration procedures. Your ophthalmologist will discuss which option best fits your individual needs and goals.
Determining If You Are a Good Candidate
Primary open-angle glaucoma responds best to canaloplasty because the procedure directly addresses the blockage in Schlemm's canal where drainage normally occurs. Pseudoexfoliative glaucoma and pigmentary glaucoma may also benefit since these conditions affect the same drainage system. Early to moderate stages of disease tend to have better outcomes than very advanced cases.
Angle-closure glaucoma is generally not suitable for canaloplasty because the drainage angle itself is too narrow or closed, though some narrow-angle or mixed-mechanism cases after lens extraction with a confirmed open angle might be considered. Neovascular glaucoma, active uveitic glaucoma, ICE syndrome, and eyes with significant angle scarring are typically poor candidates. We evaluate each case individually based on where the pressure problem originates in your eye.
If your eye pressure consistently measures above your target range despite using multiple medications, the risk of further vision loss increases. We monitor your optic nerve and visual field tests closely to determine if medical therapy is sufficient. Even if your pressure seems controlled, intolerable side effects like redness, burning, fatigue, or breathing problems from glaucoma drops may make surgery the better option.
- Pressure readings stay above the target our ophthalmologist sets for you
- Your visual field tests show continued damage despite treatment
- You experience allergic reactions or systemic effects from eye drops
- The cost or complexity of your medication regimen becomes unmanageable
Past cataract surgery does not usually prevent canaloplasty and may even be combined with the procedure if you still have a cataract. However, previous trabeculectomy, tube shunt placement, or other glaucoma surgeries can make canaloplasty more difficult or less effective. Scarring from earlier operations may alter the anatomy of your drainage system.
We carefully examine your eye and review your surgical history to determine if canaloplasty is still feasible. In some cases, the presence of a tube shunt or extensive scarring may lead us to recommend a different approach or repeat the earlier procedure type instead.
Certain health conditions can affect healing and surgical outcomes. Uncontrolled diabetes may slow recovery and increase infection risk, so we work with your primary doctor to optimize your blood sugar before surgery. Autoimmune diseases, blood clotting disorders, or medications like blood thinners require special planning to ensure safe surgery.
We also consider conditions that make it hard for you to lie flat during the procedure or follow post-operative instructions. Your overall health and life expectancy play a role in deciding whether the benefits of surgery outweigh the risks for your individual situation.
If you have both glaucoma and a visually significant cataract, we can often perform canaloplasty and cataract removal during the same operation. Combining procedures reduces the total number of surgeries you need and may improve your vision while lowering your eye pressure. The presence of an artificial lens from prior cataract surgery does not prevent canaloplasty.
- Combined surgery addresses two problems in one recovery period
- Removing a cataract can make the drainage angle easier to access
- Having a clear artificial lens improves our view during the procedure
- Your insurance coverage and out-of-pocket costs may differ for combined surgery
Preparing for Your Canaloplasty Procedure
Before scheduling canaloplasty, we measure your eye pressure multiple times and perform visual field testing to document your current level of glaucoma damage. We use gonioscopy, a special lens exam, to look directly at your drainage angle and confirm that your anatomy is suitable for the procedure. Optical coherence tomography scans show us detailed images of your optic nerve and drainage structures.
We also check the health of your cornea, measure your eye for any needed lens implant if we are combining cataract surgery, and take photographs to track changes over time. These tests create a baseline so we can compare your results after the operation.
In most cases, you should continue using your glaucoma eye drops right up until surgery day. Our ophthalmologist will give you specific instructions about which medications to keep using and which to stop, since some surgeons adjust certain drops based on inflammation, allergy, or anticipated pressure behavior. Instructions are individualized for each patient. If you take blood thinners like aspirin, warfarin, or newer anticoagulants, we coordinate with your prescribing physician to determine whether it is safe to pause them temporarily.
- Keep using your glaucoma drops unless we tell you otherwise
- Report all medications, vitamins, and supplements you take
- Discuss blood thinners with both our office and your primary doctor
- Follow any special instructions for diabetes medications on surgery day
You will not be able to drive yourself home after canaloplasty because of the anesthesia and temporary vision blurring. Plan for a responsible adult to drive you to the surgery center, wait during the procedure, and take you home afterward. Having someone stay with you for at least the first 24 hours is helpful in case you need assistance with eye drops or experience any concerns.
Prepare your home by setting up a comfortable recovery space and filling any prescriptions we give you ahead of time. Stock up on easy-to-prepare meals and arrange for help with childcare, pet care, or household chores during your first week of recovery.
We typically ask you not to eat or drink anything after midnight before your morning surgery, though you may take essential medications with a small sip of water if approved. If your procedure is scheduled for the afternoon, we will give you a specific cut-off time for food and beverages. Fasting reduces the risk of complications from anesthesia.
Bring your insurance cards, identification, and a list of all your current medications including doses. Wear comfortable, loose-fitting clothing and leave jewelry and valuables at home. Do not wear eye makeup, cologne, or perfume on surgery day, and bring your sunglasses for extra comfort on the ride home.
What Happens During Canaloplasty
Most patients receive local anesthesia with numbing injections or drops around the eye, along with mild sedation through an IV to help you relax. You remain awake but comfortable and feel no pain during the surgery. Some surgical centers may offer general anesthesia, especially if you have difficulty staying still or feel very anxious about the procedure.
We monitor your vital signs throughout the operation and adjust your sedation level as needed. Our team talks to you during the surgery to make sure you are comfortable and explains what is happening at each step if you wish to know.
For ab-externo canaloplasty, we perform a nonpenetrating deep scleral dissection. This involves creating a superficial scleral flap and then a deeper flap to carefully expose the area over Schlemm's canal. We unroof the canal and create an intrascleral lake, a space where aqueous humor can collect. A thin Descemet window is often left to allow fluid filtration. Once we locate the canal openings, we gently inject a gel-like substance to viscodilate or expand the canal before inserting the catheter.
The ab-interno approach uses microscopic instruments passed through a tiny incision in the cornea to reach the canal from inside the eye. This method creates less disruption to the outer eye tissues. Regardless of approach, we work under a high-powered surgical microscope to ensure precision.
We thread a flexible microcatheter around Schlemm's canal, ideally covering the full 360 degrees, using gentle irrigation to further open the channel as the catheter advances. The catheter has a blinking light on its tip that we can see through your eye tissue, confirming its position as it travels. In some cases, 360-degree catheterization is not achievable due to anatomic variations, scarring, or blockages, and surgeons may complete a partial canal treatment or adjust the surgical plan accordingly. Once the catheter completes its pass, we remove it carefully.
In ab-externo canaloplasty, we then place a special suture inside the canal and tie it with controlled tension to help support the canal over time. While no permanent implant device such as a metal or plastic stent is placed, the suture itself is a permanent material that remains in your eye. We close the scleral flaps with tiny stitches that dissolve over time.
Canaloplasty usually takes between one and two hours, though time varies depending on whether we combine it with cataract surgery and whether we perform the ab-externo or ab-interno technique. Most of your time in the surgery center includes preparation and recovery, not just the operation itself. Plan to spend several hours at the facility in total.
- You go home the same day with a protective eye shield
- Recovery room staff monitor you until anesthesia wears off
- We provide written instructions and prescriptions before discharge
- Someone must drive you home and stay with you that evening
Recovering from Canaloplasty
Mild to moderate discomfort, a scratchy sensation, and tearing are common during the first few days after canaloplasty. Your eye will look red or bloodshot from the surgery, and you may notice some bruising around the eyelid. Blurred vision is expected initially due to swelling, medicated drops, and the healing process inside your eye.
Over-the-counter pain relievers like acetaminophen usually manage any discomfort, though we may prescribe stronger medication if needed. Applying cool compresses gently to your closed eyelid can soothe irritation. Most of these symptoms improve significantly within the first week, but full healing takes several weeks to months.
We prescribe antibiotic drops to prevent infection and steroid or anti-inflammatory drops to reduce swelling and help your eye heal. You will need to use these medications multiple times per day on a strict schedule. Setting alarms or keeping a written log helps ensure you do not miss doses, especially if you use several different drops. We will also confirm whether to continue or temporarily stop your pre-operative glaucoma drops after surgery, since many patients need adjustments depending on eye pressure during the healing phase.
- Wash your hands thoroughly before putting in any eye drops
- Wait at least five minutes between different types of drops
- Keep track of which drops to use and how often each day
- Store medications according to package instructions, some need refrigeration
- Never let the dropper tip touch your eye or any surface
For at least one to two weeks after surgery, avoid lifting anything heavier than ten pounds, bending over with your head below your waist, or straining during bowel movements. These activities increase pressure inside your eye and can interfere with healing. We also recommend avoiding strenuous exercise, swimming, hot tubs, and activities that might accidentally bump your eye.
You should sleep with your head elevated on extra pillows and wear the protective eye shield at night to prevent accidentally rubbing your eye while you sleep. Avoid rubbing or touching your eye at any time during recovery. Keep tap water and soap out of your eye in the early post-operative period, and you may shower with care by keeping your face out of the direct stream. Most patients can return to desk work and light activities within a few days, but you may resume driving only after your ophthalmologist gives clearance. Wait for our approval before resuming sports, yard work, or heavy lifting.
We typically see you one day after surgery, then again at one week, one month, and three months to monitor your healing and pressure. These visits allow us to check for complications, measure your eye pressure, and adjust your medications as your eye recovers. Additional appointments may be scheduled if we have any concerns or if your pressure needs closer watching.
Consistent follow-up is crucial because some complications develop gradually and early detection makes treatment more effective. We also use these visits to determine when you can safely stop your post-operative drops and resume normal activities. Missing appointments can put your surgical success at risk.
Eye pressure often drops within the first few weeks after canaloplasty, but it can take up to three to six months to see the full effect as swelling resolves and the drainage channel stabilizes. Some patients notice immediate improvement while others experience fluctuating pressures during the healing period. Inflammation from surgery can temporarily raise pressure before it settles into the lower range. Early eye pressure can be variable, and some patients need temporary additional drops or interventions during the healing phase.
We track your pressure trend over multiple visits rather than relying on any single measurement. Even if your pressure is not as low as we hoped initially, continued improvement often occurs as healing progresses. Patience is important because the final result takes time to develop.
Possible Complications and Warning Signs
Mild discomfort, light sensitivity, tearing, and the feeling that something is in your eye are all normal during the first few weeks. Fluctuating vision and seeing glare or halos around lights can occur as your eye adjusts. These temporary effects usually fade as healing continues and rarely require any intervention beyond your prescribed medications.
- Bloodshot or pink appearance of the white part of your eye
- Slightly blurred or hazy vision that improves over weeks
- Mild irritation or foreign body sensation
- Increased tearing or watery eyes in bright light
A small amount of bleeding inside the eye, called hyphema, can occur when blood refluxes from Schlemm's canal during or after the procedure. You may also see visible blood on the white part of your eye. Small hyphemas usually clear on their own within a couple of weeks. However, you should contact us if you notice worsening blur with rising pressure, a blood layer that increases rather than decreases, or if the blood is accompanied by pain, headache, or nausea. Lack of clearing by your scheduled follow-up visit also warrants discussion.
We watch for excessive inflammation by checking your eye under the microscope at follow-up visits. Controlled inflammation from the surgery is expected, but too much can cause scarring or pressure elevation. We adjust your steroid drop frequency based on how much inflammation we see. Most inflammation responds well to medication and gradually settles down. Rarely, inflammation may persist or worsen, requiring additional treatment or closer monitoring to prevent long-term damage.
Contact our office right away if you experience sudden vision loss, severe eye pain that does not improve with pain medication, or a significant increase in redness and swelling. Flashing lights, new floaters, or a curtain or shadow in your vision could signal a retinal problem. Fever, pus-like discharge, or worsening symptoms despite medication may indicate an infection.
Glaucoma-specific urgent symptoms include severe headache with nausea or vomiting, which may signal an acute pressure spike, markedly decreased vision with a sensation that your eye feels firm or hard, and sudden halos around lights with significant pain. If you cannot reach our office and your symptoms are severe, seek emergency care at the nearest hospital or emergency department immediately. We provide emergency contact information for after-hours concerns so you can reach us anytime during your recovery.
While canaloplasty has a favorable safety profile compared to traditional filtering surgeries, all eye surgeries carry risks. We review these with you in detail before you consent to the procedure so you can make an informed decision.
- Intraocular pressure spike requiring additional drops or a secondary procedure
- Persistent or large hyphema that does not clear on the expected timeline
- Descemet membrane detachment or corneal swelling that may blur vision
- Transient low eye pressure or choroidal effusion, though these are less common than with trabeculectomy
- Infection or endophthalmitis, which is rare but vision-threatening
- Cataract progression if your natural lens remains in place
- Need for additional glaucoma surgery, including trabeculectomy, tube shunt, or other MIGS procedures
- Suture-related problems such as over-tensioning, breakage, or cheese-wiring through tissue
- Inability to complete 360-degree catheterization due to anatomic blockages or variations
- Formation of peripheral anterior synechiae or scarring in the drainage angle
Studies suggest that canaloplasty successfully lowers eye pressure in a majority of patients at one year, but outcomes vary widely depending on how success is defined. Different studies use different target pressures, percent reductions, medication use thresholds, and whether combined cataract surgery was performed. Some patients achieve enough pressure reduction to stop all glaucoma medications, while others still need fewer drops than before surgery.
If your pressure rises again over time, we may add back glaucoma medications or recommend additional laser or surgical treatment. Canaloplasty does not always provide a permanent cure, but it can delay the need for more invasive surgery and reduce your dependence on eye drops for an extended period. We continue monitoring your glaucoma for life regardless of surgical outcomes.
Frequently Asked Questions
Many patients can reduce or eliminate their glaucoma medications after successful canaloplasty, but some still require one or two drops to keep pressure in the target range. Your need for medication depends on how much your pressure drops and what pressure level your optic nerve can tolerate without further damage. We make this determination during your follow-up visits over several months.
Ab-interno canaloplasty is often classified within the MIGS category as an angle-based procedure, while ab-externo canaloplasty is typically considered more invasive due to the scleral dissection and deeper tissue work involved. MIGS encompasses a range of devices and techniques, including trabecular micro-bypass stents, goniotomy, and viscodilation systems. Some MIGS procedures treat segments of the drainage system, while others including certain ab-interno canaloplasty systems can treat larger portions of the canal. Ab-externo canaloplasty with 360-degree catheterization and suture placement may achieve greater pressure reduction but involves a longer recovery compared to the smallest MIGS procedures. The best choice depends on your disease severity, target pressure, and surgical goals.
You should not feel pain during canaloplasty because of the local anesthesia and sedation we provide. Afterward, most patients describe mild soreness, scratchiness, or pressure rather than sharp pain. Any discomfort typically responds well to over-the-counter pain medicine and improves within a few days as your eye begins to heal.
Repeating canaloplasty is possible but more challenging because scar tissue from the first surgery may make it harder to open the canal again. If canaloplasty does not maintain your pressure long-term, we more commonly add medications back or consider a different type of glaucoma surgery like trabeculectomy or a tube shunt. Your individual circumstances and the reason for initial failure guide our recommendation for next steps.
We begin to see pressure trends within the first month, but the final result often takes three to six months to fully develop as all swelling resolves and the canal healing completes. We define success over the long term by whether your pressure stays low enough to prevent further glaucoma damage with fewer or no medications. One single pressure check does not tell the whole story, which is why consistent follow-up over many months is essential.
No, canaloplasty cannot bring back vision already lost to glaucoma because the damaged optic nerve fibers do not regenerate. The goal of surgery is to preserve your remaining vision by lowering eye pressure and slowing or stopping further nerve damage. Some patients notice clearer vision after surgery because of improved pressure control or simultaneous cataract removal, but this is not a restoration of previously lost visual field areas.
Getting Help for Canaloplasty for Glaucoma
If you are struggling to control your eye pressure with medications or considering surgical options for your glaucoma, our ophthalmologist can evaluate whether canaloplasty is right for you. We will review your complete eye health, discuss the benefits and risks of different procedures, and create a treatment plan tailored to your specific needs and goals for preserving your vision.