Glaucoma valve

Diagram showing the flow of aqueous humour in the eye.

A glaucoma valve is a medical device used in the treatment of glaucoma, a group of eye conditions that can lead to optic nerve damage and vision loss. The valve is designed to help reduce intraocular pressure (IOP) by facilitating the drainage of aqueous humour from the eye.

Anatomy and Physiology

The eye is a complex organ responsible for vision. It contains a clear fluid called aqueous humour, which is produced by the ciliary body and flows through the pupil into the anterior chamber of the eye. The fluid then drains out of the eye through the trabecular meshwork and into the Schlemm's canal.

In patients with glaucoma, the drainage of aqueous humour is impaired, leading to increased intraocular pressure. This pressure can damage the optic nerve, resulting in vision loss.

Mechanism of Action

A glaucoma valve is surgically implanted into the eye to create an alternative drainage pathway for the aqueous humour. The device typically consists of a small tube that is inserted into the anterior chamber and connected to a plate that is placed on the surface of the eye, under the conjunctiva.

The valve regulates the flow of aqueous humour out of the eye, helping to maintain a normal intraocular pressure. This can prevent further damage to the optic nerve and preserve vision.

Indications

Glaucoma valves are indicated for patients with open-angle glaucoma, angle-closure glaucoma, and other types of glaucoma that do not respond to medication or laser therapy. They are also used in cases of neovascular glaucoma and congenital glaucoma.

Surgical Procedure

The implantation of a glaucoma valve is typically performed under local anesthesia. The surgeon makes a small incision in the conjunctiva and inserts the tube into the anterior chamber. The plate is then positioned on the surface of the eye and secured in place. The conjunctiva is closed over the plate to complete the procedure.

Complications

As with any surgical procedure, there are potential complications associated with glaucoma valve implantation. These may include infection, bleeding, hypotony (low intraocular pressure), and tube erosion. Regular follow-up with an ophthalmologist is essential to monitor for these complications and ensure the proper functioning of the valve.

Related Pages

• Glaucoma
• Intraocular pressure
• Optic nerve
• Aqueous humour