This sheet answers common questions about having a Hydrus microstent implant. If you would like further information, or have any particular worries, please do not hesitate to ask your nurse or doctor.

In all cases, a specialist will explain the Hydrus microstent to you and answer any questions you may have.

What is a Hydrus microstent?

A Hydrus microstent is a tiny tube, the size of an eyelash, which is implanted into the eye to improve the outflow of fluid and reduce pressure. When implanted, you won’t be able to feel it in your eye and it won’t be visible to the naked eye.

Who can/should have the implant?

The device can help those suffering with glaucoma to manage the condition better. It is typically offered to patients on pressure-lowering eye drops who are undergoing cataract surgery

Although the device will not reverse any damage already caused by glaucoma or bring back any lost vision, having a Hydrus microstent may allow you to reduce your glaucoma eye drops or prevent the need for additional eye drops.

How is the implant procedure done?

The procedure to implant the device is usually performed at the end of cataract surgery.

Immediately before the procedure, you will usually be given an anaesthetic injection just under superficial layers of the white of the eye. The surgeon will ask you to turn your head to one side and then position a special lens on the eye, which allows them to see where they will implant the microstent. The device is inserted in your eye through one of the incisions that has already been made during the earlier cataract surgery.

Before your procedure

If you take blood thinning medications, your doctor may advise you to stop these a certain number of days prior to the surgery.

After your procedure

You will have an eye pad and shield over the eye which can usually be removed the following morning. You will receive a follow up appointment in the eye clinic.

You will be given a card containing important information about the microstent which you should keep. If you need an MRI scan in the future, you should show this card to the person conducting the MRI scan. The device is made of titanium and is considered safe in most MRI scanners.

What are the success rates of Hydrus microstent?

A five-year clinical trial found glaucoma patients who had cataract surgery and a Hydrus microstent implant had a 66% chance of no longer needing glaucoma drops, compared to 46% in the group who underwent cataract surgery alone.

The risk of requiring additional glaucoma surgery in those who had the Hydrus microstent group was also significantly less compared to those who only had cataract surgery.

Risks and side-effects

A small amount of bleeding at the time of implantation is normal and may result in hazy vision for a few days. There is a small risk of excessive bleeding which may require additional surgery

There is a small chance that it may not be possible to implant the Hydrus microstent or that the stent may not implant in the correct position, in which case it will be removed. If this happens you will be advised by your doctor whether any additional treatment is required.

There is a chance that, despite successful implantation, you may still need additional glaucoma surgery in the future if your eye pressure is judged to be too high.

Alternatives to the Hydrus microstent

The alternative to combined cataract and microstent surgery is to have cataract surgery alone. If pressure needs to be further lowered afterwards, your doctor will consider additional pressure lowering drops or a laser treatment known as selective laser trabeculectomy.

Alternative surgical treatments include Preserflo microshunt, trabeculectomy and aqueous shunts such as Ahmed valve, Baerveldt or Paul glaucoma drainage implants.