What is a Preserflo MicroShunt?

The Preserflo MicroShunt is an eight-millimetre tube which is placed in the eye to help lower eye pressure in patients with glaucoma. It can reduce the need for glaucoma medication.

The tube is made of a synthetic and non-toxic material called SIBS (styrene-block-isobutylene-block-styrene), which is degradation resistant and not rejected by the body.

As it is not metallic one can safely undergo MRI or CT scan if needed. It will not set off airport scanners.

Why have I been advised to undergo this surgery?

The main purpose of the Preserflo MicroShunt is to lower the eye pressure. Lowering of the eye pressure helps prevent glaucoma progression.

The Preserflo MicroShunt is suitable for patients with uncontrolled eye pressure - even after using glaucoma medication. It is also advised for patients who are intolerant or unable to use eye drops regularly.

You may have been recommended a Preserflo MicroShunt implant to prevent the progression of glaucoma.

How does the Preserflo MicroShunt work?

Increased pressure in the eye is the main reversible risk factor for glaucoma progression.

The Preserflo MicroShunt drains the excess fluid from inside the eye to the outside under the conjunctiva (the thin skin like membrane on the eye) forming a bleb. This is a small fluid reservoir beneath the skin of the eye. This new drainage pathway helps lower the eye pressure.

One study with three years of follow up reported an average pressure reduction of 55% and a reduction in the average number of glaucoma drops needed.

What are the other alternatives to this surgery?

Treatment options for glaucoma include:

  • Eye drops
  • Laser treatment
  • Surgery (trabeculectomy - an operation to create new drainage by creating a ‘trap door’ in the white of the eye).

Generally, surgery is suggested for patients with uncontrolled eye pressure despite using eye drops, if they are not able to use eye drops or are not suitable for laser treatment. You can always discuss treatment options with your ophthalmologist.

Before the operation

Before your operation, you will be asked to attend a pre-operative assessment appointment to check you are fit for the procedure. If you have been booked to have surgery under general anaesthetic, your suitability for this will also be assessed.

Please continue to use any eye drops and tablets we may prescribe for your glaucoma, unless directed otherwise by your ophthalmologist.

If you take any blood thinning medication (e.g., Warfarin) or have had bleeding problems in the past, please discuss this with your ophthalmologist before surgery.

During the operation

The operation is normally performed under local anaesthesia. You will be given an anaesthetic injection which will numb the area around the eye. This may cause some discomfort and a pressure sensation around the eye. Your vision may also be affected temporarily for a few hours.

Mitomycin C, which is an anti-scarring medication, is applied under the skin of your eye during the surgery. This helps to increase the long-term success of the Preserflo MicroShunt.

The thin skin-like membrane covering the white of your eye (conjunctiva) will be opened so that the Preserflo MicroShunt can be placed inside your eye. The conjunctiva will then be closed with stitches.

These stitches may either be removed later in clinic or, in some cases, dissolve by themselves. The surgery will usually take under 30 minutes.

After the operation

You will be able to go home after the surgery. It is better if there is someone to accompany you. Your operated eye will be covered with an eye patch or a clear plastic shield.

You will be given instructions on the day of surgery on when to remove your eye patch. You will also be given eye drops to use in your operated eye and will be given instructions on when to start using the eye drops.

There will be two different drops to use in the operated eye: an antibiotic for two weeks and a steroid, the dose of which will be determined at each follow-up clinic visit. You will have a follow-up clinic appointment one to two days after your surgery.

Your eye may be slightly blood shot and swollen for a few days. Your vision may also be blurry for one to two weeks after the procedure. Do not rub or press on the eye after the operation. As this can happen when you are sleeping, we will ask you to continue wearing the plastic shield at night for one to two weeks or sometimes longer if the pressure remains low.

For the first month after surgery, you should avoid bending down and avoid strenuous activity such as lifting heavy weights, swimming, tennis, jogging and contact sports. Please ensure you wear goggles if swimming after complete healing of your surgery. Most people take one to two weeks off work after surgery; however, the length of time will depend on the nature of your work.

Do I need to continue taking my regular glaucoma medication?

After the operation, we will ask you to stop using glaucoma medication in the operated eye, but it is very important to continue using eye drops if needed in the other eye. Sometimes, if the eye pressure remains high or slowly increases, we may ask you to restart some eye drops in the operated eye.

Will I be able to fly after the procedure?

It is safe to fly after surgery, however you will need to be seen few times by your surgeon in the first two months. We suggest discussing this with your ophthalmologist before the surgery.

Risks and side-effects

Serious sight-threatening complications such as bleeding at the back of the eye or infection inside the eye are rare. It is not unusual to have some bleeding into the front of the eye. If this happens, your vision could be blurred for one to two weeks or occasionally longer.

Like any other glaucoma surgery, the eye pressure lowering effect of the Preserflo MicroShunt may wear off with time. If this happens, you will need to restart your glaucoma drops or have further procedures to control your eye pressure.

There is also a small risk that the Preserflo MicroShunt might become exposed, in which case further surgery would be required. There is also a risk of very low eye pressure after the operation, which is much less than with traditional glaucoma surgery. Persistent very low pressure is uncommon.