Patient Information

Eye surgery leaflets

Colchester Eye Centre
Colchester Primary Care Centre
Tel: 01206 487 106
Monday to Friday, 9am to 5pm


Hydrus microstent

A procedure to lower eye pressure

This booklet aims to help you understand the Hydrus implant, which is one way of managing your glaucoma.

The Hydrus microstent is a tiny tube which is implanted in the eye to reduce eye pressure. The procedure is performed at the same time as cataract surgery.


Open angle glaucoma and intraocular pressure

Your eyes produce a liquid called aqueous humor, which is essential for healthy eyes. Often in glaucoma this liquid does not flow out of the eye properly and the pressure in your eye increases. This increased pressure can damage your optic nerve.

When you come to clinic we measure your eye pressure. This is important because most people with open angle glaucoma have no early symptoms or eye pain. If left untreated, over time it may result in
permanent vision loss and blindness.


The Hydrus

The Hydrus device is made of a tiny tube. It creates a path that allows the fluid inside the eye to bypass
the natural drain of the eye and it is normally only used alongside cataract surgery. It is not visible outside the eye, and cannot cause any symptoms.

The Hydrus will not cure your glaucoma but will help to slow down any progression.


Cataract surgery with Hydrus

A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to ageing.
Symptoms of cataracts may include cloudy or blurry vision, colours that seem faded, difficulty with glare such as sunlight and oncoming headlights, and the need for more frequent change of glasses.

Cataract surgery involves the removal of the cloudy natural lens and replacement with an artificial (intraocular) lens. When you have cataract surgery along with the Hydrus as part of a single operation the Hydrus is implanted in your eye immediately after your cataract is removed and the artificial lens
has been implanted.


Before your operation

Your eye will be examined before your operation.

Measurements of your eye and eye pressure will determine which type of artificial lens is best for you.

Depending on which medications you are taking, you may be asked to stop taking them for few days before your operation or you may be asked to start new medication.


During your operation

You will have a local anaesthetic in your eye so you will be awake during the operation. You will not be able to see what is happening but you may be aware of a bright light. There will be some discomfort as
the stent is inserted and you may have a dull ache or headache during the surgery as well as couple of
days after.

During the operation you will be asked to keep your head still and lie as flat as possible. The whole operation takes approximately 45 minutes.

The surgeon makes a very small cut in the eye, softens the lens with sound waves and removes it through a small tube. The back layer of the lens capsule is left behind. The artificial implant is inserted to replace the cataract. Immediately after the cataract portion of the surgery is completed, the surgeon will implant the Hydrus.


After the operation

After the operation, an eye pad or shield will be placed over your eye to protect it. You will spend a short time in the recovery area and then you will be able to go home. It is important that you have someone to take you home as you will not be able to drive. You will be given instructions by the nurses regarding the removal of the eye pad the next day and information about your next appointment.

You will also be given an implant card containing important information about the Hydrus. You should keep the card safe. If you need an MRI scan in the future you will need to show the doctor your implant card; although it is made of titanium, the Hydrus implant is considered to be MRI safe.

You will be monitored after your surgery to make sure your eye pressure is controlled. If needed we will recommend additional treatments, including appropriate medication or other treatments to control your eye pressure.


After surgery

You will be given eye drops to help your eye heal with instructions on how to use them. You may be given some antibiotics to prevent infection. You will usually be examined a month after your surgery to
check your eye pressure, which may change during the first several days after surgery. Sometimes a
pressure check on day one may be required.



The Hydrus lowers the eye pressure, which helps in the management of your glaucoma and delays any
disease progression.


Potential risks

The risks of the Hydrus and cataract operation are similar to the risks of having cataract operation
alone. There are, however, some additional risks associated with Hydrus, and these will be discussed
with you before your operation.

There is a small risk that the stent may not be implanted successfully or in the planned position.

The stent may become blocked over time and, in rare cases, you may need a second operation to clear the blockage.

Quite often microscopic bleeding occurs inside the eye following correct placement, and this tells us that the implantation was successful. It can cause temporary hazy vision but this will resolve

Although uncommon, there are other risks that may occur such as excessive bleeding during surgery, inflammation and progression of your glaucoma.

General risks of eye surgery include reactions to medicines, infection, inflammation, vision changes,
increased eye pressure which are all treatable.


Post-operative instructions

  • No rubbing or pressing 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 a few weeks.
  • Reading, watching television and using the computer are fine.
  • Do not drive until the doctor tells you it is safe to do so.
  • Most people need 1 to 2 weeks off work after the operation.
  • To reduce the risk of infection, keep the eye dry for two weeks.
  • Please ensure you wear goggles when swimming.
  • It is safe to fly after the operation.


Contact us

If you have any problems such as reduced vision, painful red eye or discharge after your operation
please ring the Eye Clinic for advice and support.
Please telephone 01206 487 106, Monday to Friday, 9am to 5pm.

Out of hours (weekdays 5pm to 7pm; weekends and bank holidays 11am–4pm)
please telephone 01206 286 882, or contact your GP, or go to the Urgent Treatment Centre or Emergency Department at Colchester Hospital.

In an emergency, call NHS 111 or use the 111 website, or go to an urgent treatment centre or your
nearest emergency department (A&E).


Your experience matters

We value your feedback. Please help us improve our services by answering a simple question, in our
online survey – “Overall, how was your experience of our services?”
This survey is known as The Friends and Family Test.



The Recite feature on this website attempts to provide digital accessibility and translation support. If you would like to make a request for a leaflet to be produced in a different format please see our PALS contact page in order to contact the team and make a request. If you require a translation please see our translation information page. ESNEFT are actively attempting to achieve accessibility regulation compliance under the Public Sector Bodies (Websites and Mobile Applications) (No.2) Accessibility Regulations 2018.

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