What is the Ahmed Valve?
In patients with glaucoma, the buildup of aqueous humor fluid causes high intraocular pressure that can eventually damage vision. The Ahmed valve is a tiny device that is implanted into the eye to reduce intraocular pressure (IOP).
The Ahmed valve is one type of aqueous shunt implantation that drains the aqueous humor fluid from inside the eye to a small capsule (often called bleb) behind the eyelid. Draining the fluid continuously by this method reduces pressure on the optic nerve and can prevent further loss of vision.
How Does It Work?
The ophthalmologist places a tiny silicone tube into the front of the eye. The tube is attached to a very small device called a plate, which is placed under the skin of the conjunctiva (the transparent membrane over the white of the eye). This is usually under the upper eyelid and is not visible to the naked eye.
Several weeks after surgery, a capsule or “bleb” is formed. Aqueous humor can then drain through the shunt to the bleb. Eventually, fluid in the bleb dissipates into the body as it is absorbed by the blood vessels.
Where Will My Doctor Perform The Procedure?
Ahmed valve glaucoma surgery is performed in our outpatient eye surgery center, where our patients receive local anesthesia to make them comfortable. In certain patients, general anesthesia may be indicated, but this rare. The surgery only takes about 1 hour to complete.
How Successful is the Ahmed Valve?
Research studies are ongoing, but success rates for aqueous shunt procedures are within the 60-80% range after 5 years. However, every patient’s eye anatomy and stage of glaucoma is different. Many patients can eliminate their prescription eyedrops altogether following surgery, while others are able to maintain a healthy IOP with lower dosages.
Your Long Beach ophthalmologist will perform a full evaluation to determine if the Ahmed valve is the best option to treat your glaucoma.
What Are The Complications?
- Inflammation and redness as the eye adjusts to a foreign body (usually resolves in 4 to 6 weeks).
- Elevated IOPs often occur before the bleb is fully functional and draining properly. Occasionally, a brief procedure is needed to resolve the high IOP.
- Hypotony, or very low IOP (under 6 mm) can damage vision. This is rare when the Ahmed valve procedure is used.
- Clogging of the shunt or too much scarring around the implant.
- Corneal injury (very rare)
Who Should Have This Procedure?
Glaucoma doctors used to limit Ahmed Valve shunt procedures for use in patients who have not achieved reduced eye pressure after previous eye surgery. Currently, the use of aqueous shunt surgery has increased, as research has shown good results.
Eye surgeons are using this type of surgery as the primary, or initial surgery for glaucoma patients. Ahmed valve surgery is recommended for patients who have experienced the following:
- Failed trabeculectomy surgery
- Glaucoma caused by diabetes or other neovascular diseases
- Glaucoma related to uveitis
- Trauma-induced glaucoma
A major advantage of the Ahmed device is that the valve technology helps prevent too much fluid from draining, and thus reduces the chance of the IOP going too low. In addition, the surgery may require less post-operative care than some other aqueous shunt procedures.
Ahmed Valve Surgery, Long Beach, CA
Only an eye care specialist can determine the best glaucoma treatment for you. At Eye Physicians of Long Beach, our team of eye care experts can answer your questions and provide a thorough explanation of your glaucoma treatment options. Contact us to schedule your appointment today!