XEN STENT FOR GLAUCOMA
Glaucoma is the name for a group of eye conditions which cause damage to the optic nerve at the back of the eye. The naturally made fluid in the eye is unable to drain away properly which can result in a build up of pressure within the eye. The pressure is usually treated with eye drops. If the eye drops fail to reduce the pressure, damage to the optic nerve will cause permanent loss of sight. To lower the eye pressure a surgical procedure known as a filtration surgery can be carried out. Traditionally this is done by an operation known as Trabeculectomy. This surgery is still the gold-standard operation that is able to achieve low level eye pressure, however, it is generally a long operation requiring incision to the conjunctiva and several weeks to fully recover from the operation. More recently, Xen Gel stent has become available to achieve similar outcomes with minimal surgical trauma to the eye. Xen Gel Stent is a form of Minimally Invasive Glaucoma Surgery.
What does XEN stent involve?
The Xen Gel stent is a very fine flexible stent made of a porcine gelatin material. It creates a new pathway for fluid inside the eye to drain out of the eye, thereby relieving pressure. The Xen Gel stent is as fine as a single stand of human hair. The material integrate well with the body and will not cause rejection.
Traditional operation can take up to an hour however Xen Gel stent can be performed within 10 minutes under local anaesthetic. After a successful Xen Stent it may be possible to reduce glaucoma eye drops. If the Xen Stent is not successful the operation may need to be repeated or further treatment may be required. The aim of the operation is to reduce the risk of further
damage to the optic nerve. It is not aimed to improve your sight, but will hopefully help protect your vision in the longer term.
How eye pressure is controlled by XEN stent?
The Xen Gel stent allows fluid to slowly and continuously drain out of the eye in a safe manner. The excess fluid drains into a small blister (called “bleb”) under the mucous layer on the white of your eye (conjunctiva) that is covered by your top eyelid. The bleb is generally not noticeable.
During the procedure
Xen Gel Stent generally take 10 minutes. Xen Gel Stent surgery under local anaesthetic is not painful although you may feel a sensation of pressure in the eye at some stages during the operation. A sterile cover will be placed over your face and the other eye to keep the area clean, but it will be kept clear from your nose and mouth by a stand with circulates fresh air. Your eye will be kept open using a special instrument, so you don’t have to worry about keeping the eye open yourself. It is important that you don’t move suddenly during the operation. The bright microscope light prevents you from seeing what is going on and many patients see whorls of blue or purple light during the operation. The surgeon will discuss the way to communicate with him/her: you may choose to hold a nurse’s hand which you can squeeze if you need to communicate with the surgeon. If you feel you need to cough or sneeze you can tell us this, but take care not to move your head until the surgeon says it is safe to do so.
What are the risks?
Some of the risks involved are:
• For a period of time pressure in the eye may become too high or too low. If eye pressure is too high, your surgeon will help you reduce pressure with adjustment known as “Needling” which converts a small draining bleb into a larger bleb with better function. If eye pressure is too low (<5 mmHg), then often your surgeon would manage with conservative methods first but occasionally will require return to theatre for injection of a material that can improve eye pressure.
• In some cases a cataract may develop (~10%). This can be treated by an operation if necessary.
• Serious complications are rare, but rarely the sight can get worse after the Xen stent and not recover.
What is the alternative to XEN stent?
Alternative to XEN stent is trabeculectomy operation .
Below is a video of Dr George Kong's XEN stent operation.