Glaucoma – what is it, its causes, diagnosis, and treatment options.  

Glaucoma is an ocular condition that affects millions of people worldwide. In fact, it is estimated that 300,000 Australians have it but astonishingly up to 50% of them are unaware. 

Often referred to as the ophthalmic sneak thief, in its early stage, glaucoma can often go undiagnosed as its initial symptoms are difficult to detect and only affect peripheral vision. This often means that by the time it is detected its progression is advanced. It essentially ‘sneaks up’ on those who have it and ‘steals’ their vision. Gradually damaging the optic nerve over time, if left undiagnosed and untreated glaucoma can lead to irreversible vision loss.  

However, if discovered it can be successfully treated and managed to prevent further vision loss. 

In this blog we explain what glaucoma is, its causes, how it is diagnosed, and the treatment options currently available.  

What is glaucoma? 

Glaucoma is a group of eye diseases resulting in loss of vision due to damage to the optic nerve located at the back of the eye. Most commonly this visual loss is gradual, and starts in the peripheral vision, so is often not noticed by the patient until visual loss starts to affect central vision. 

Often this occurs in conjunction with elevated pressure in the eye, otherwise referred to as intraocular pressure, but can also develop with normal eye pressure. 

What are the causes of glaucoma? 

There are many potential underlying causes for glaucoma and thorough history, examination and testing are required to determine the individual cause in each case. However, some of the below factors can often contribute to its development and include: 

• Abnormalities affecting only the eye 
• Systemic conditions such as diabetes 
• Use of some medications such as steroid medications 
• Prior trauma to the eye  
• Reduced blood supply to the optic nerve can contribute to its damage and subsequent vision loss 
• Hereditary indicators – glaucoma tends to run in families, indicating a genetic predisposition to the condition 
• Age – the risk of developing glaucoma increases with age, particularly after the age of 60 
• Certain ethnic groups are at a higher risk of developing glaucoma compared to others 

How is glaucoma diagnosed? 

Early detection of glaucoma is crucial to minimise vision loss. When you come to the clinic for your initial assessment, you will have several tests done prior to seeing your ophthalmologist.  

These tests may include: 

• Visual acuity 
• Visual field testing 
• OCT scan of the optic nerve and the macular 
• Auto refraction test 

Additional tests may be conducted during your consultation, and which are tailored to your specific circumstances. 

Following these tests, your ophthalmologist will conduct a comprehensive examination of both the front and back of your eye.  

During this initial assessment it is likely that your pupil will need to be dilated and your will not be able to drive afterwards and for a period of 24 hours, so it is a good idea to have someone attend with you, or to arrange transport home afterwards.  

What are the treatment options for glaucoma? 

While there is no cure for glaucoma, and your ophthalmologist and you will need to manage your condition for your lifetime, various treatment options are available to manage the condition and prevent further vision loss. The choice of treatment options as detailed below will depend on the type and severity of glaucoma and your recommended best course of action.  

Medical Therapy 

Medical therapy is the least invasive and consists of eye drops, and in some cases tablets oral medications. Eye drops need to be used daily, or in some cases twice per day, and is usually a permanent routine. There are multiple different types of eye drops used to treat glaucoma. If you and your ophthalmologist decide this is the best option for you, you will work together to find the right eye drop regime and for many patients, their glaucoma can be controlled with just one eye drop a day. 

Laser Therapy 

There are a number of laser therapy choices used to treat glaucoma as detailed below. 

• Selective laser trabeculoplasty (SLT) is a laser procedure which allows fluid to drain more effectively through the trabecular meshwork of the eye.  In simple terms, its the eye structure that is responsible for fluid drainage of the eye and that can become compromised or is not working efficiently. The procedure can be completed in clinic rooms and requires only anesthetic drops. It is usually performed over two sessions, to reduce the amount of inflammation in the eye. 
• Laser peripheral iridotomy (PI) is a treatment where a microscopic hole is made in the iris, the coloured part of the eye. Creating this hole prevents fluid getting trapped behind the iris, which can cause high intraocular pressure. Again, this procedure can be performed in the clinic room, with anesthetic drops and typically will require anti-inflammatory drops for one week after the procedure. 
• Cyclodiode is a laser procedure which works to decrease the amount of fluid produced by the eye, and therefore lowers the intraocular pressure. It is performed either in a procedure room in clinic or in theatre and requires a short acting local anesthetic block. Typically it will take four weeks to take effect, so any glaucoma medications you have been using will need to be continued during this time.  

Surgical Therapy 

There are a number of surgical therapy choices used to treat glaucoma as detailed below. 

• Minimally Invasive Glaucoma Surgery: Also referred to as MIGS, these procedures typically involve the use of stents inserted at the time of cataract surgery, to address both cataract and glaucoma issues. There are several different devices available, and your ophthalmologist will be able to determine and discuss with you your best option.  
• Trabeculectomy is a traditional glaucoma procedure, where an incision is made in the white of the eye (called the sclera) to create a trap door, forming a new drainage pathway for fluid to exit the eye. This procedure is done in theatre and is typically performed when your glaucoma is not responding to other treatment options. 
• Minimally Invasive Bleb Surgery: This procedure uses a modern device called the Preserflo and is used to offer minimally invasive glaucoma surgery for patients with moderate to severe glaucoma which is getting worse. Similar to a traditional trabeculectomy, however, due to some design features of the Preserflo, the device allows the procedure to be carried out with a smaller incision, allowing for faster recovery. A small implant is inserted into the eye during the procedure, to allow fluid to drain from the eye and lower the intraocular pressure.  

Conclusion 

Glaucoma is a lifelong condition that if left untreated will gradually but progressively cause loss of vision. However, with early detection and ongoing management, treatment pathways are able to preserve vision.  

Dr Carmen Oakley is a consulting ophthalmologist at Adelaide Eye & Laser Centre and is a specialist in glaucoma.  

For those patients diagnosed with glaucoma, Dr Oakley will discuss with you the best treatment options at your initial consultation, while taking into consideration your lifestyle and other medical problem. 

If you would like to find out more click here. If you would like to book an appointment with Dr Oakley, or speak with her please do not hesitate to contact us here.