Tube Surgery

Tube Surgery
Tube Surgery - Image source:

A stent/tube for glaucoma is designed to be inserted into the eye to promote the drainage of the aqueous humour (fluid in the front portion of the eye) out of the eye. These may be combined with cataract surgeries. Mr Agarwal will speak to you about these if he thinks they may be a good fit for your situation.

A glaucoma stent or tube is designed to reduce the pressure in the eye to control glaucoma. It will not restore vision that has already been lost.

After the surgery you may notice some redness and swelling of the eye and lids. Immediately following the surgery, you will have a patch on the eye and you should wear this at night to protect the eye while you sleep.

With some tubes and shunts, the drainage is not opened immediately post-operatively to allow the wound time to heal. This will mean that the pressure in the eye may not be lowered in the weeks immediately following the surgery, do not become discouraged by this.

A bleb (fluid filled blister) is often present under the upper eyelid following the surgery. Occasionally this may be visible at one side of the eye, depending on the required placement of the tube/shunt. 

Blurring of vision

You may find that your vision is blurred for the first 1-2 weeks after the operation, until the operation site is healed. The operation will not restore any sight you have already lost, it is to save the sight you have.

Discomfort in the eye

Mild pain and discomfort are common in the post-operative period, this is partly due to the surgery itself. The eye should return to a normal feeling after approximately 2 months.

Eye drops

You will be required to use eyedrops to help with the healing process and may still need to use your glaucoma drops. Mr Agarwal will provide instructions on what drops to use. 

It is important to continue any eye drops to the UNOPERATED eye unless Mr Agarwal tells you otherwise. Use drops in the operated eye after the surgery as directed by Mr Agarwal.

If local anaesthetic is used, the eye will remain numb throughout the surgery. If you are aware of any pain, please let Mr Agarwal know, as this is unusual. The initial numbing of the eye is done with a drop followed by an injection. You may be aware of slight discomfort and pressure as the anaesthetic is delivered. 

Throughout the surgery if you are awake, you may see bright lights and hear people talking. Only your eye will be visible to Mr Agarwal, the remainder of your face will be covered with a sterile drape to keep the operation sterile.

Often, at the end of the surgery a special drug is used to help prevent scarring of the passage for the fluid. This is called mitomycin C (MMC) and is a type of anticancer drug. This is applied to only a certain part of the surgical site. This drug has been used for many years in eye surgery and has been found to be safe; however, is not what it was originally licensed for and it’s use if termed ‘off license’. 

A patch of donor tissue is implanted to protect the thin layer of tissue over the shunt. This may be corneal or scleral tissue from an eye or sometimes, pericardium from a heart. All tissue undergoes testing to ensure there are no traces of disease such as syphilis, hepatitis and HIV. Having a donor tissue may mean in the future you cannot donate tissues or organs.

Complications during tube/shunt surgeries are rare.

As with any surgery, the risk of infection post operatively is present (1 in 1000). Inflammation and requirement for a second surgery are also possible. 

Severe complications are rare; however, can happen if the pressure in the eye drops very low or too quickly. Bleeding is the most serious risk and occurs in less than 1 in 1000 patients. Mr Agarwal takes every precaution to avoid this however it is often unpredictable. 

Some patients find the bleb of the tube/shunt changes the position of the eyelid. This may improve with time.

A tube/shunt may not completely lower the eye pressure to the target level and drops may still be required. 

You may have a change in glasses prescription following the surgery. Until your eye has completely healed, you should not update your glasses. Some patients notice their vision is not as sharp as it was before the operation, and this may be due to the formation of cataract which is often accelerated following any surgery to the eye. Cataract surgery can be discussed if this occurs. 

Very rarely a patient may experience double vision when a tube is implanted due to the size of the plate attached to the tube. Usually this settles over a month’s period.

Very rarely, a tube may become blocked, erode or rub against the cornea (the clear portion of the eye) if any of these things happen, a further surgery will likely be indicated to correct them.

Although proven to be safe and approved treatments, tubes/shunts post-operative data is constantly being collected to influence use and their indication. This means that unexpected complications may occur many years after implantation. 


  • Wear your glasses throughout the day as normal, if you have them. 
  • Continue to read and watch TV. 
  • Wear sunglasses to reduce light sensitivity, if needed.
  • Wash you hands before inserting drops.
  • Wear an eye shield at night for as long as recommended by Mr Agarwal.
  • Keep to a routine with drop insertion. If you have a smart phone, there are apps you can download to help you with this or many patients make a chart.  
  • Arrange to take some time off work if you’re working, this can depend on the individual and type of work required. Office workers often take 2 weeks off while those working in more physically demanding or dusty environments may need to take 1 month off. 
  • Ask any questions you may have.



  • Wear contact lenses until cleared by Mr Agarwal. 
  • Wear eye make-up for at least 2 weeks ideally 4 weeks following surgery.
  • Touch the tip of the eye drop bottle with your fingers or to your eye. 
  • Bend over, stain or undertake strenuous activities like weight lifting running, biking or inversions in yoga.
  • Put pressure on your eye for at least four weeks, this will aid in the healing process. 
  • Update your glasses within the first 3 months of surgery.
  • Be afraid to ask questions.


While care has been taken to compile accurate information and to keep it up to date, Mr Agarwal cannot guarantee its correctness and completeness. The information provided in this information sheet is designed to support care and is not a substitute for professional healthcare advice, by a qualified doctor or other healthcare professional, which will be tailored to a patient’s individual circumstances.

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