Glaucoma is known as ‘the silent thief of sight’ because patients can loose their outer-most vision over time with no other symptoms. Due to the chronic nature of the disease sight is stolen bit by bit and by the time you realize it you may already have significant loss of vision. According to the South African Glaucoma society 50% of people don’t even know they have the disease this percentage can go up to 90% in developing countries. Many people believe that blindness is not preventable and just a part of normal ageing, programs that target blindness and conditions that cause it, can change not only the lives of individuals but also the country as a whole. Visit your optometrist for yearly screening for glaucoma from the age of 40 years.
Over 40 years? Screen for Glaucoma
1 in 25
People 40 + years in Africa have Glaucoma
4 in 25
According to the World Health Organisation 2010
What is Glaucoma?
Glaucoma causes damage to your eye’s optic nerve. Increased pressure in your eye is caused by fluid that builds up in the front part of your eye. This pressure damages your optic nerve. Blindness from glaucoma can often be prevented with early treatment.
What causes Glaucoma?
Your eye constantly makes aqueous, a clear fluid in the front part of your eye. It is responsible for keeping the shape of your eye correct and nourishing the eye. It is not the same as tears. New aqueous is constantly produced in your eye and the same amount should drain out through the drainage angle. This keeps your intraocular pressure (IOP) or the pressure in your eye stable. If the drainage angle is not working correctly, fluid builds up. Pressure inside the eye increases. This damages the optic nerve that is responsible for sending light signals to your brain so you can see. This nerve consists of hundreds of thousands of nerve fibers that are killed one by one due to the high pressure. You will develop blind spots in your vision. Amazingly your brain fills in these blind spots and although some detail will be missing you might not suspect anything until you have lost a great part of your vision. If all of the fibers die, you will be blind. Managing the pressure should however spare your nerve fibers and prevent blindness.
Two types of Glaucoma
Primary open-angle glaucoma
This is the most common type of glaucoma. The drainage angle does not drain fluid as well as it should. It happens gradually like a clogged drain. Pressure in the eye builds and starts to damage the optic nerve. Open angle glaucoma is painless and causes no sudden vision changes. Some people have optic nerves that are sensitive to normal eye pressure. They have a higher than normal risk to get glaucoma. Their pressure might not be that high and regular eye exams are important to find early signs of damage to their optic nerve.
Angle-closure glaucoma (closed-angle glaucoma or narrow-angle glaucoma)
This type happens when someone’s iris (colored part of the eye) is very close to the drainage angle in his or her eye. The iris can block the drainage angle. You can think of it like a piece of plastic over a sink drain. The drainage angle gets completely blocked and eye pressure rises very quickly. This is an emergency and you should call your ophthalmologist immediately or you might go blind.
The signs of an acute angle-closure glaucoma attack:
• Sudden blurry vision
- Severe eye pain
• Nausea & vomiting
• Seeing rainbow-colored halos around lights
Angle-closure glaucoma can also develop slowly. This is called chronic angle-closure glaucoma. You have no symptoms at first. You only realize you have it when the damage is severe or you have an acute attack. Angle-closure glaucoma can cause blindness if not treated immediately.
It is essential to check both the pressure in your eye and examine the optic nerve to screen for glaucoma. An optometrist can do both and refer you to an ophthalmologist if they see any signs of glaucoma.
Your ophthalmologist will:
How high is your risk for glaucoma?
Your risk is higher if you:
• are older than 40
• have family members with glaucoma
• are of African or Hispanic descent
• have high eye pressure
• are far-sighted or near-sighted
• had a previous eye injury
• have corneas that are thin in the center
• have thinning of the optic nerve
• have diabetes, migraines, poor blood circulation or other health problems affecting the whole body
If you have more than one of these risk factors you have an even higher risk of glaucoma.
Damage due to glaucoma cannot be reversed. It is permanent. Further damage can however be prevented with medicine and surgery.
Treatment options include medication, laser surgery and hospital surgery.
Glaucoma is usually controlled with eye drops. The eye drops lower eye pressure. They either reduce aqueous fluid production or improve drainage at the drainage angle. The aim is to prevent further vision loss. All medications can have side effects. Some drugs can cause problems when combined with other medications. Tell your doctor about all the medicine you take regularly.
Glaucoma drops have side effects that include:
• burning or itching of the eye
• red eyes or redness of skin around the eyes
• blurred vision
• eyelash growth
• changes in your eye color, the skin around your eyes or eyelid appearance.
• change in your pulse and heartbeat
• change in your energy level
• change in breathing (more so if you already have asthma or breathing problems)
• dry mouth
Never change or stop taking your glaucoma medications without talking to your ophthalmologist. Make sure that you do not run out of your medication.
There are two main types of laser surgery to treat glaucoma. Laser surgery is done in the ophthalmologist’s office on an outpatient basis.
• Selective laser trabeculoplasty is done for people who have open-angle glaucoma. A laser is used to make the drainage angle work better. Fluid flows out properly and eye pressure is reduced.
• Iridotomy. This is for people who have angle-closure glaucoma. A laser is used to create a tiny hole in the iris. The hole helps fluid flow to the drainage angle.
Glaucoma surgery in hospital creates a new drainage channel for the aqueous to leave the eye.
- Trabeculectomy. This is where your eye surgeon creates a tiny flap in the sclera (white part of your eye). A bubble (like a pocket) is also formed in the conjunctiva called a filtration bleb. It is usually hidden under the upper eyelid and cannot be seen. Aqueous humor will be able to drain out of the eye through the flap and into the bleb. In the bleb, the fluid is absorbed by tissue around your eye, lowering eye pressure.
- Glaucoma drainage devices. Your ophthalmologist may implant a tiny drainage tube in your eye. It sends the fluid to a collection area. Your eye surgeon creates collection area (reservoir) beneath the conjunctiva that covers the white part of your eye. The fluid is absorbed into nearby blood vessels.
- Minimally-invasive glaucoma surgery (MIGS) can be done at the time of cataract surgery for patients with mild to moderate open angle glaucoma. It requires no additional incisions other than those needed for cataract surgery itself. The device creates a bypass through the blockage site. Patient recovery time is usually rapid. Clinical studies show that most patients experience a reduction in IOP and a reduction in reliance on glaucoma medication.
Your role in glaucoma treatment
Treating glaucoma successfully is a team effort between you and your doctor. Your ophthalmologist will prescribe your glaucoma treatment. It is up to you to follow your doctor’s instructions and use your eye drops.
Once you are taking medications for glaucoma, your ophthalmologist will want to see you regularly. You can expect to visit your ophthalmologist about every 3-6 months. Once diagnosed make sure that you are registered for glaucoma, a PMB condition, at your medical aid. Glaucoma is a Prescribed Minimum Benefit (PMB) disease and once registered these visits are at least partially paid for from your PMB benefit and not from your day-to-day benefit. If you have any.