Advanced glaucoma is considered to be enough loss of vision to produce significant symptoms and functional impairment. These symptoms can include, but are not limited to, difficulty in performing visual tasks like reading, driving, seeing in low light situations, etc., and tiring easily from those visual tasks.
Normally, advanced glaucoma is the result of elevated pressure in the eye (intraocular pressure) that has lasted for a substantial amount of time resulting in significant loss of vision. A considerable number of patients with glaucoma have their disease under control with medication for a long time before it progresses further to the advanced stage. Sometimes, however, patients might ignore serious symptoms or may not see their doctor regularly for checkups, resulting in more serious advancement of the disease.
Regular checkups are so important to be able to diagnose, monitor and treat glaucoma from an early stage. Intervention depends partly on what target eye pressure your doctor has decided is suitable for you and the amount of permanent damage that has occurred. If the disease is progressing, treatment may need to advance from medical treatment, such as drops, to surgical intervention to help halt the progression of glaucomatous vision loss.
There are several surgical ways to treat advanced glaucoma. Your Ophthalmologist will discuss these options with you and based on their expertise and experience will work with you to determine which option is most suitable for your situation. One of your options may be a glaucoma drainage device (GDD).
GDD is an implant that will create an alternate pathway for the fluid (aqueous) in your eye to drain, helping to regulate your intraocular pressure (IOP). A GDD consists of a tube, which is attached to a plate.
Implant may be a deceiving term! The GDD is surgically placed on the white part (sclera) of your eye. It gets positioned between or under the eye muscles about 8-10mm back from the outside of the coloured part (iris) of your eye. The plate is held in place with permanent sutures and the tube is inserted into the anterior chamber of your eye to release the fluid.
An “Ahmed Glaucoma Valve” is a type of glaucoma drainage device (GDD) available to you. Labtician distributes this product to hospitals in Canada on behalf of New World Medical, Inc. (Rancho Cucamonga, CA). It is available in either a silicone (flexible material) version or polypropylene (rigid material) version. The Ahmed Valve is a uni-directional valved GDD. This means the valve self regulates your intraocular pressure (IOP) and when that pressure reaches a certain level the aqueous will flow out of your eye. The valve also helps to prevent over drainage by restricting aqueous flow when your IOP drops below a certain level.