Glaucoma Surgery and Treatment

About Glaucoma

Glaucoma is a common condition in which increased pressure within the eye damages the optic nerve. It can affect anyone, but it is most common in people aged 60 and over. The condition results from a build-up of aqueous fluid at the front of the eye and, if left untreated, can lead to loss of vision.

In the early stages of glaucoma most people have no symptoms, which means the only way to detect the condition is through regular eye checks. Although glaucoma can affect anyone, it is known to run in families: if a member of your immediate family has glaucoma, you are at higher risk of developing the condition.

Before the treatment of glaucoma

You may experience severe eye pain, see halos around lights, or have nausea or vomiting, headache or loss of vision.

After the treatment of glaucoma

If treated promptly, your symptoms will subside and there should be no lasting damage to your vision.

How do I know if I need glaucoma surgery?

The most common form of glaucoma, known as open-angle glaucoma, usually affects both eyes and causes no obvious symptoms in its early stages. It occurs when an obstruction affects the circulation of the aqueous humour flowing into and out of the eye, causing the pressure within the eye to rise.

Because it progresses so slowly, many people are unaware that their vision is deteriorating. For this reason it is usually picked up during a routine eye examination, or when your doctor decides you may be at risk and refers you to a glaucoma specialist.

Exactly why some people develop the condition is still not clear.

Risk factors

The following are known risk factors:

• Your ethnicity: Glaucoma is more common in people of Asian, African, Caribbean and Hispanic descent.
• Your age: The condition becomes more common as you get older. It is less common in people under the age of 40 (rarely, children can also be affected).
• Your family history: Glaucoma is known to be hereditary, so your risk is increased if a member of your immediate family has been diagnosed with it.
• You suffer from certain medical conditions: Hypertension (high blood pressure), diabetes, heart disease or sickle cell anaemia.
• You have been diagnosed with certain eye conditions: Thin corneas, high intraocular pressure, severe myopia or hypermetropia, or a significant history of poor vision.
• You regularly take high doses of certain steroid medicines: Such as prednisolone.

Other forms of glaucoma

Other, less common, forms of glaucoma include:

• Angle-closure glaucoma: This occurs when the drainage of fluid from the eye suddenly becomes blocked, causing a rapid rise in eye pressure. It is caused by a change in the position of the iris. It tends to occur in one eye and, when it develops very quickly, it is a medical emergency. When one eye is affected, the other eye is also at risk.
• Secondary glaucoma: This is due to a separate underlying condition, such as uveitis (an inflammatory condition of the eye), cataracts or diabetes.
• Childhood glaucoma: Also called congenital glaucoma, this is a rare form that develops at a young age.

What happens during Glaucoma Surgery?

There is a variety of surgical treatments, all of which aim to reduce the pressure within the eye. If glaucoma surgery is considered appropriate, a specialist glaucoma surgeon has a number of options available; the choice will depend on the type of glaucoma, its severity and any other health problems you may have.

The laser and surgical options for glaucoma include:

• Selective laser trabeculoplasty (SLT): A form of laser glaucoma surgery used to treat open-angle glaucoma, in which the surgeon increases the drainage of fluid from the eye.
• Laser peripheral iridotomy (LPI): Another type of laser glaucoma surgery, in which the pressure within the eye is reduced by making a small opening in the iris itself. It is commonly used in cases of angle-closure glaucoma.
• Trabeculectomy (Filtering Surgery): A surgical procedure in which a tiny area of the eye wall (sclera) is removed to allow the aqueous humour to drain.
• Antiglaucoma Valve Surgery: An option for all types of glaucoma, this involves placing a tiny tube within the eye through which the aqueous fluid can drain.

Selective laser trabeculoplasty (SLT) is a popular choice for treating the most common forms of glaucoma. It is often the procedure of choice when eye drops and/or other medicines have failed to reduce the pressure within the eye sufficiently, or when their side effects are too severe. It may need to be repeated in the future.

SLT is performed by a specialist glaucoma surgeon. Your eyes are numbed with drops and a special contact lens is placed on the eye. The surgeon then uses a high-energy laser to make up to 100 tiny burns on the trabecular meshwork within the eye. The procedure takes less than 10 minutes to perform and causes very little discomfort.

How can a glaucoma specialist help with this condition?

Glaucoma is usually diagnosed during a routine eye examination, although sometimes your doctor may refer you if they think you may be at risk. If you are diagnosed with the condition, regular monitoring will be necessary. The tests for glaucoma are simple and painless. The specialist will use drops to dilate the pupil, allowing them to examine your optic nerve in detail, and images will be taken so that they can be compared at future visits. You will also have tests of your peripheral field of vision and an eye pressure test, known as tonometry. The first line of treatment is usually eye drops, medication, or a combination of the two.

How do eye drops and medications work?

Eye drops work in one of two ways: they either increase the drainage of aqueous humour from the eye or reduce its production. Either way, this helps lower the eye pressure. Oral medication can do the same, with carbonic anhydrase inhibitors and beta-blockers the most commonly used. Medication does, however, often have unwanted side effects, including redness and stinging of the eyes, blurred vision, irritation and allergies; in some cases, the drugs may affect the cardiovascular system. It is important to tell your glaucoma specialist about any other medication you are taking, to prevent adverse drug interactions.

Glaucoma surgery and laser treatment options

If these side effects become excessive, or if eye drops and medication fail to control the problem adequately, your glaucoma specialist is likely to recommend surgery. Whether this involves microsurgery or laser surgery, it may mean you no longer need drops and/or medication to control the glaucoma. All the surgical options work by increasing drainage to reduce the pressure within the eye.

The various surgical options are as follows:

• Trabeculoplasty: Opens up the drainage channels of the eye
• Peripheral Iridotomy: Creates a tiny hole in the iris that helps the aqueous humour to flow freely
• Cyclophotocoagulation: The middle layer of the eye is treated to reduce the production of aqueous humour
• Trabeculectomy: A filtering procedure created by removing a tiny area of the eye wall
• Antiglaucoma valve: A small tube is placed in the eye through which the aqueous humour can flow.

Not all operations are suitable for every type of glaucoma, nor is each one the right option for every individual. Your glaucoma specialist will decide on the best solution together with you. Whichever option is chosen, you will need regular monitoring afterwards to make sure the treatment is working.