Glaucoma is the name given to a group of eye diseases that damage the optic nerve that links the retina to the brain. Often, glaucoma is associated with too much pressure inside the eyeball. It is a leading cause of damage to vision or blindness in people over 40 but can affect people of any age. If glaucoma is detected early, treatment can prevent or reduce vision loss in most patients.
Types of glaucoma
The aqueous humour is a fluid produced by the ciliary body. It drains out of the eye through a sieve-like structure called the trabecular meshwork. Glaucoma occurs when the speed of aqueous humour pumped into the eye by the ciliary body is greater than the speed of aqueous humour flowing out through the trabecular meshwork.
Types of glaucoma include:
Open-angle glaucoma - aqueous humour cannot drain properly
Angle-closure glaucoma - flow of aqueous humour is blocked
Normal pressure glaucoma - occurs despite average intraocular pressure
Childhood glaucoma - rare and often hereditary
Congenital glaucoma - present at birth
Secondary glaucoma - due to other conditions of the eye.
Your medical history
Your ophthalmologist needs to know your medical history to plan the best treatment for you. Tell your ophthalmologist about any health problems you have. Some may interfere with treatment, surgery, anaesthesia, recovery and ongoing medical treatment following recovery.
A decision to have surgery
As you make the decision whether to have surgery, make sure that you understand the risks, benefits and limitations of surgery. If you do not have surgery, your symptoms and condition may continue to worsen.
Only you can decide if surgery is right for you. If you have any questions, ask your ophthalmologist.
Glaucoma surgery may be performed under local or general anaesthesia.
Treatment with eye drops or tablets is usually tried before surgery, unless surgery is urgent. Various surgical procedures are available.
Laser surgery techniques include:
Laser trabeculoplasty - small areas of the trabecular meshwork are treated to improve drainage.
Laser iridotomy - a small hole made in the iris allows aqueous humour to flow more freely.
Cyclophotocoagulation - parts of the ciliary body are destroyed so that less aqueous humour is produced.
The most common incisional surgery is called a filtering procedure. In a filtering procedure called a trabeculectomy, the ophthalmologist creates a channel through the wall of the eyeball to drain aqueous fluid.
Cyclocryosurgery uses liquid nitrogen to reduce the ability of the ciliary body to produce fluid.
Possible risks and complications
Glaucoma surgery is safe and effective, but does have risks of complications. These are more fully outlined in the complete RANZCO patient education pamphlet and should be discussed with your ophthalmologist.