What is glaucoma?
Glaucoma is the name given to a group of eye diseases in which the optic nerve at the back of the eye is slowly destroyed. In most people this damage is due to an increased pressure inside the eye - a result of blockage of the circulation of fluid in the eye or blocked drainage. In other patients the damage may be caused by poor blood supply to the vital optic nerve fibres, a weakness in the structure of the nerve, or a problem in the health of the nerve fibres themselves.
Over 300,000 Australians have glaucoma. While it is more common as people age, it can occur at any age. As our population becomes older, the proportion of glaucoma patients is increasing.
Usually the condition is painless.
- Glaucoma is the leading cause of irreversible blindness worldwide.
- One in 10 Australians over 80 will develop glaucoma.
- First degree relatives of glaucoma patients have an 8-fold increased risk of developing the disease.
- At present, 50% of people with glaucoma in Australia are undiagnosed.
- Australian health care cost of glaucoma in 2005 was $342 million.
- The total annual cost of glaucoma in 2005 was $1.9 billion.
- The total cost is expected to increase to $4.3 billion by 2025.
- The dynamic model of the economic impact of glaucoma enables cost-effectiveness comparison of various interventions to inform policy development.
Source: Tunnel Vision. The economic impact of Open Angle Glaucoma, Centre for Eye Research Australia, 2008
Chronic (primary open-angle) glaucoma is the most common type. It is painless.
Damage progresses very slowly and destroys vision gradually, starting with the side vision. Early on the person remains unaware of any problem. Glaucoma may only be noticed when a majority of nerve fibres have been damaged, and a large part of vision has been destroyed. This damage is irreversible. It is progressive and usually relentless. Treatment cannot recover what has been lost. Treatment can arrest, or at least slow down the damage process. That is why it is so important to detect the problem as early as possible, to be able to start treatment with as little damage to the vision as possible.
Although anyone can get glaucoma, some people have a higher risk, those with
- A family history of glaucoma
- Short sightedness (myopia)
- Long sightedness (hyperopia)
- Eye injuries
- Past or present use of cortisone drugs (steroids)
Most patients will see Dr Kert every six months for a glaucoma assessment. The assessment will involve checking the vision, the intraocular pressures and looking at the optic disc. Other tests are usually performed such as visual fields, OCT imaging of the optic disc and glaucoma parameters and fundus photography.
At each visit, Dr Kert will assess the progression of your glaucoma and may make changes to your glaucoma treatment. The treatment and surveillance of the condition are life long as there is no cure for glaucoma.
Treatment for Glaucoma
- Topical medication (eye drops)
Eye drops are usually the first line management of glaucoma. Instructions of how to instil eye drops can be found here.
- Selective Laser Trabeculoplasty, or SLT
Selective Laser Trabeculoplasty, or SLT is a form of laser surgery that is used to lower intraocular pressure in glaucoma. It is used when eye drop medications are not lowering the eye pressure enough or are causing significant side effects. It may sometimes be used as initial treatment in glaucoma. SLT has been in use for 12 years in Australia and around the world.
A trabeculectomy is an operation to make the pressure lower inside the eye.
Who is a candidate for SLT?
Patients who have open-angle glaucoma (the drainage system in the front part of the eye is open) and are in need of lowering of their intraocular pressure (IOP) are eligible for the procedure. Your eye doctor will make the final determination if you are a candidate.
How does it work?
Laser energy is applied to the drainage tissue in the eye. This starts a chemical and biological change in the tissue that results in better drainage of fluid through the trabecular meshwork drain and out of the eye. This eventually results in lowering of intraocular pressure. It may take 1-3 months for the laser to effect a lowering of the eye pressure.
Why is it called Selective?
The type of laser used has minimal heat energy absorption because it is only taken up by selected pigmented tissue in the eye. Sometimes it is referred to as a 'cold laser.' Because of this, the procedure produces less scar tissue and has minimal pain.
What are the risks of SLT?
One key aspect of SLT is a favourable side effect profile, even when compared with glaucoma medications. Post-operative inflammation is common but generally mild, and treated with observation or eye drops or an oral non-steroidal anti-inflammatory drug. There is an approximately 5% incidence of intraocular pressure elevation after laser, which can be managed by glaucoma medications and usually goes away after 24 hours.
How effective is SLT?
SLT lowers the intraocular pressure by about 30% when used as initial therapy. This is comparable to the intraocular pressure lowering of the most powerful and commonly used class of glaucoma medication (prostaglandin analogs). This effect may be reduced if the patient is already on glaucoma medications.
How long does the effect last?
The effect will generally last between 1-5 years, and in rare cases, longer than that. If it does not last at least 6-12 months, it is usually not considered successful.
What happens if it wears off?
If SLT is effective at lowering intraocular pressure but this wears off over several years, the procedure can be repeated but the second treatment may not be as effective as the first and may not last as long. If SLT is not initially successful, repeat treatment is not likely to be effective. Alternatively, glaucoma medication can be used if the effect wears off over time.
What happens if it doesn't work?
If SLT fails to lower the intraocular pressure, then the glaucoma is treated by other means such as medications or conventional surgery such as trabeculectomy. The laser does not affect the success of these other types of treatment.
What is the cost?
Since the procedure is an accepted glaucoma treatment, and is approved, it is covered by Medicare. The cost will be discussed with you prior to proceeding. The Medicare Safety Net can assist you in covering most of the out of pocket expenditure.
Will I still need to use glaucoma medications?
Some patients can be controlled with just laser treatment. Others require additional intraocular pressure lowering and may therefore need to use glaucoma medication as well. Think of the SLT as equivalent to one glaucoma medication. Just as some patients will require more than one glaucoma medication to control their intraocular pressure, some may also require laser plus one or more glaucoma medications. It is important to remember that SLT is not a cure for glaucoma, just as medication and surgery are not.
Whatever method is used to treat glaucoma, continuing appropriate follow up and testing at Darling Downs Eye is critical.
If you have any further questions feel free to call the team at Darling Downs Eye to discuss further.
Why has my doctor recommended this operation?
Glaucoma may get worse if the pressure inside the eye is not low enough. Trabeculectomy is recommended when eye drops are not controlling the pressure and there is a significant risk that glaucoma is going to cause further damage to your sight.
What is trabeculectomy?
A trabeculectomy is an operation to make the pressure lower inside the eye. It involves making a new channel in the white wall of the eye (sclera), through which fluid flows out into a space underneath the outer layer of the eye (conjunctiva). A successful trabeculectomy creates what we call a ‘bleb’, a small elevation which is usually covered by the upper eyelid.
What anaesthetic is used?
Trabeculectomy is usually done as a day case under general anaesthetic.
What happens after the operation?
Frequent follow-up is required in the first few weeks and months after this operation. All patients need to be reviewed the day after surgery then, if all is well, a week later and again one to three weeks after that. The exact timing of these and future reviews depends on how the eye is settling down, and more frequent visits are quite often required.
The first few weeks after the operation are very important for checking the eye and for carrying out adjustments. Most of these adjustments are minor and will be done as part of the outpatient visit. It is best to avoid planning any holiday within two months after the operation.
If you already have a holiday planned, you do need to discuss this with your doctor, and schedule the surgery appropriately.
What will my vision be like?
It is common for the eye that has had the surgery to be quite blurred for a few weeks, sometimes longer. There is no need to change your glasses straight away, but some patients will benefit from updating their glasses sooner than they normally would, though it is best to wait for three months while things settle. You can resume driving (if this applies to you) if your vision is sufficient for you to meet the legal requirements. Trabeculectomy does not improve vision - its purpose is to prevent sight loss in the future.
What can I and can't I do after trabeculectomy?
Returning to work
Most people can return to office-based work two weeks after the operation though sometimes longer is needed. It is usually wise to wait at least a month before resuming physically strenuous work or work in a dusty/dirty environment. Dr Kert will advise you in more detail about this at your postoperative checks.
You can use your eyes (for reading, television, computers etc) as soon as you wish - this will not harm your eye. Gentle exercise (walking) is fine, but you should expect to avoid strenuous exercise (running, ball sports, fitness workouts), or lifting heavy objects for at least a month after the operation.
Swimming or immersing the eye should be avoided for at least one month - please ask at your check-up if you wish to resume swimming. It may be useful to keep the clear shield on your eye, or wear glasses for the first week after the operation, for the protection that it offers.
How successful is trabeculectomy?
The operation helps lower the pressure in the eye in about 80% of cases, and most patients will not need glaucoma drops in the eye that has had the operation. A lower pressure is beneficial to nearly all patients with glaucoma, but glaucoma can still progress - in some cases even after a ‘successful’ trabeculectomy.
What are the risks and complications of trabeculectomy?
We always need to consider the risks as well as the potential benefits before going ahead with an operation. If this surgery has been recommended then Dr Kert will have judged that the risk to your sight from glaucoma (without the operation) is greater than the risks of the operation itself.
For most patients trabeculectomy achieves a lower pressure without any significant problems; however, all operations do have some risks and for trabeculectomy these include:
- Reduced vision
This is very common in the first two weeks, due to swings in the pressure
- Minor bleeding inside the eye
These typically settle within the first few weeks. Some patients (five to eight percent) may have some degree of permanently reduced vision after the operation. Loss of all vision in the eye due to the surgery itself is very unusual, but as with all intraocular surgery can very rarely occur.
This usually settles within a few weeks, but some patients experience long-term discomfort. These symptoms are usually mild and can be controlled with artificial tears.
- Increased likelihood of cataract
This is quite common within five years. If it does occur, it can be treated in the normal way. In some patients a trabeculectomy works less well if a cataract operation is performed subsequently. Your doctor may elect to perform cataract surgery prior to the trabeculectomy.
- Infection and loss of vision in the eye
There is a small risk of infection after any eye surgery including trabeculectomy. Additionally, after trabeculectomy there is a permanently-increased risk of infection getting inside the eye. The risk is small, roughly one in a thousand.
Further surgery may be required to make the operation succeed, or to correct low pressure. It is not unusual for an additional procedure of some sort to be required - usually this is a much shorter procedure than the trabeculectomy itself.
If you have any further questions feel free to call the team at Darling Downs Eye to discuss further. Trabeculectomy is usually done as a day case under general anaesthetic.