Glaucoma Drainage Implant

What is a Glaucoma Drainage Implant?

Glaucoma is caused by a failure of the aqueous humor within the eye to drain correctly. This causes the pressure inside the eye to rise, compressing, and damaging the optic nerve. If this is allowed to progress unchecked, it can cause permanent loss of vision.

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The initial treatment of the disease is usually eye drops. This might also be combined with oral medication. If this fails to have an adequate effect, laser or conventional surgery usually follows. The more complex types of glaucoma, or when the initial treatments stop working, often warrant the placement of glaucoma drainage implants. This provides an alternative channel through which the aqueous humor can drain, therefore lowering the pressure.

Glaucoma Implants: Types and Alternative Names

There are two basic types of glaucoma implants—valved and non-valved. They’re sometimes referred to as “aqueous shunts” or “glaucoma drainage devices”. The first glaucoma implant type was developed in 1969. Today, the implants are highly advanced and involve the placement of a tiny device within the eye that increases the natural drainage process (and therefore reduces the pressure).

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The difference between the two types is that one utilizes a tube along which the fluid flows, and the other promotes drainage along its surface. Both types work to provide the same result.

All About Glaucoma Drainage Implant Surgery

The insertion of a glaucoma drainage implant is usually carried out under local anesthetic with appropriate sedation. This means you’ll be barely aware (if at all) that the procedure is taking place, but you’ll still be able to go home the same day. The operation typically takes around an hour. Your vision might be blurred for some time afterward, so you’ll need someone to drive you home after the appointment.

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Whatever glaucoma implant type is used, it requires your eye surgeon to position the device in a pocket beneath the conjunctiva towards the back of the eye. It’s very thin and is curved to follow the natural curvature of the eye. This is attached to a small filament, or tube, that’s inserted into the eye. This creates a drainage channel along which the fluid flows.

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After the procedure you’ll be given an eye patch to wear for a few hours (possibly overnight), some medication to promote healing, and you’ll need to refrain from anything strenuous for a few weeks. It’s usual to have to continue taking your glaucoma medication and attend regular consultations to monitor the eye pressure.

Risks of Having a Glaucoma Implant?

Several thousand glaucoma drainage implant procedures are carried out every year in the US. It’s a proven and safe form of treatment. However, as with any surgical procedure, there are risks involved. While rare, your ophthalmologist will discuss these with you.

The main risks of having a glaucoma drainage implant are:

• Overcorrection: Whereby too much fluid drains from the eye and the pressure becomes too low

• Scarring: Either on or within the eyeball

• Infection: Occurring either post-procedure or at a later date. Symptoms include pain and reddening of the eye and/or surrounding tissues. It must be treated straight away, so requires urgent attention from your ophthalmologist

• Bleeding: Either around or into the chamber of the eye

• Double vision

• Loss of vision

• Cataracts

If you take anticoagulants or aspirin, this can increase the risk of complications with regards to extended bleeding after the procedure. You’ll need to stop taking them for a period before the operation. Your eye surgeon will advise as to when and for how long you should cease the medication.

Post-operative complications may warrant a second surgical procedure to correct the problem or for the implant to be removed.

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