Glaucoma

What is glaucoma?

Glaucoma is a group of eye diseases that damage the optic nerve. It often affects both eyes, usually to varying degrees. As most cases won’t have any symptoms, one of the best ways to detect glaucoma is during a routine eye test – that’s why it’s so important to have one regularly.

What causes glaucoma?

The eyeball contains a fluid called aqueous humour, which is constantly produced by the eye. Any excess fluid is drained from the eye through tiny channels and tubes. When the fluid cannot drain properly, pressure builds up in the eye.

Glaucoma typically develops when this increased pressure damages the optic nerve, which connects the eye to the brain, and harms the nerve fibres from the retina, the light-sensitive nerve tissue that lines the back of the eye.

In acute glaucoma cases this pressure rises rapidly to higher levels, even causing pain.

Risk factors of glaucoma

Anyone can develop glaucoma, but there are several risk factors which make developing it more likely.

Your risk of developing glaucoma is four times higher if you have a close blood relative who has it
Age plays a big part. Chronic glaucoma affects up to two in every 100 people over the age of 40 and around five in every 100 people over 80
Higher levels of short-sightedness are linked to the chronic form of glaucoma, and long-sightedness to the acute form
Consistently raised pressure in the eye, called ocular hypertension (OHT), is a risk factor
People of African-Caribbean origin have about a four-times higher risk of developing chronic forms of glaucoma compared to those of European origin
Acute glaucoma is generally much less common, however people of Asian origin are at higher risk of developing this type of glaucoma compared with those from other ethnic groups
People with diabetes may be at higher risk of developing glaucoma
Very high blood pressure can lead to an increase in intraocular pressure, which can increase your risk of developing glaucoma
Low blood pressure can lead to insufficient blood supply to the optic nerve, which can also cause problems
Eye conditions, surgeries or injuries: injury to the eye can cause secondary open-angle glaucoma, either immediately after the injury or some years later
Regular users of steroids are at higher risk of developing glaucoma

Everyone has fluid inside their eyes that is regulated by tiny tubes and drainage channels in the eye. Sometimes these channels don’t work as well as they should or can become blocked, and this can cause the pressure in the eye (intraocular pressure) to rise.

A high intraocular pressure can be a significant risk factor in developing glaucoma. If the pressure is consistently high, it can start to affect the sensitive nerve fibres at the back of the eye.

That’s why having regular eye tests is so important – it means we can keep an eye on your pressure levels every time you see us, along with all the other eye health checks we carry out.

Types of glaucoma

The main types of glaucoma are as follows:

Chronic or primary open-angle glaucoma

Chronic or primary open-angle glaucoma is the most common type of glaucoma. It develops gradually and painlessly, so an eye test is usually the only way to detect it.

Primary angle-closure glaucoma

Sometimes known as acute glaucoma, primary angle-closure glaucoma is usually treated as a medical emergency.

This is because, unlike chronic open-angle glaucoma, primary angle-closure glaucoma happens quickly due to a sudden rise in eye pressure, and if it’s not treated quickly, it can lead to sight loss.

Traumatic glaucoma

Traumatic glaucoma can develop after an eye injury – either a blunt trauma or something that penetrates the eye. It can happen either at the time of the injury or some time later.

Hereditary glaucoma

Is glaucoma hereditary?

There is at least a four-times higher risk of developing glaucoma if you have a close blood relative who has it.

Studies⁽⁶⁾ have shown that if members of your immediate family (a parent or a sibling) have glaucoma, your risk of developing early-onset glaucoma increases by almost 10 times. Your risk of developing glaucoma also increases if you have an identical twin who has the condition.

Congenital glaucoma

Congenital means a condition is present at birth and congenital glaucoma does affect a very small number of babies. The onset of congenital glaucoma happens before the age of three and is caused by mutations in two genes (CYP1B1 or LTBP2).

These genes are inherited as an autosomal recessive trait, where both parents are carriers of the mutation but do not have glaucoma themselves. Their children can inherit both copies of the mutation, one from each parent, leading to the development of glaucoma.

What are the symptoms of congenital glaucoma?

Some of the signs of possible eye trouble in children can be difficult to spot. For childhood glaucoma, symptoms may include:

Unusually large eyes due to increased pressure
The cornea (the transparent front section of the eye) may appear cloudy
The child may display excessive tearing and photosensitivity, like closing one or both eyes in bright conditions
There may be signs and symptoms that indicate poor peripheral (side) vision, for example running or bumping into objects
Some children with childhood glaucoma may complain of discomfort or pain in the eye if there is a rapid increase in intraocular pressure
Babies with this condition may become irritable and refuse to feed⁽⁷⁾

Developmental glaucoma

Developmental glaucoma is another type of childhood glaucoma that appears between the ages of 10 and 20 years. It is associated with mutations in genes involved in the development of the eye — particularly in the front part of the eye and in structures that drain fluid from the eye.

These developmental issues are usually inherited from one of the parents who is carrying a dominant gene, and may be associated with other developmental anomalies. For example, someone with developmental glaucoma may also have abnormal teeth or hearing loss.

Myocilin mutations

People diagnosed with glaucoma before the age of 35 may have a form of glaucoma associated with a mutation in a myocilin gene. Mutations in this gene are also inherited as autosomal dominant traits, meaning there’s a chance that parents with this form of glaucoma could pass it on to half of their children.

However, any form of glaucoma can have multiple gene variants that can place you in the risk group. It’s also important to note that even if someone in your immediate family has glaucoma, it doesn’t necessarily mean you will develop it yourself.

What are the symptoms of glaucoma?

There are various types of glaucoma and symptoms will differ depending on which type you have.

If you have chronic glaucoma, you might not realise you have it because it’s painless and affects your peripheral (outer) vision. Without regular checks you may not notice there’s a problem until your start to lose your more central vision.

Acute glaucoma develops much faster as a result of sudden pressure build-up in the eye. Although rare, it is usually painful and is often accompanied by:

Blurred vision
Haloes around lights
Headache
A red eye
Nausea/vomiting

If you get these symptoms, it is important to seek immediate assistance. Contact your optician or local accident and emergency department.

Even if the symptoms go away you should contact your optician as soon as possible as repeat episodes can cause damage to your eyesight.

How will glaucoma affect my vision?

Many people with early-stage glaucoma have enough vision to work, read, drive, and live independently. However, if you’ve been diagnosed with glaucoma, it’s important to use the eye drops you’ve been prescribed exactly as instructed.

Neglecting treatment, including missing medications, can make your vision worse, and in some cases can even lead to vision loss⁽⁸⁾.

Diagnosing glaucoma

Glaucoma will usually be diagnosed during a normal eye test. As well as looking at the overall health of your eye and the structures within it, you’ll have a series of quick and painless tests that help to spot any signs of glaucoma.

Tests

Tests for glaucoma

A glaucoma test is a series of medical evaluations performed to detect and diagnose glaucoma. The most common glaucoma test is the eye pressure test. Other glaucoma tests include the visual field test, digital retinal photography and optic nerve assessment.

Eye pressure test (tonometry)

An instrument called a tonometer is used to measure the pressure inside your eye – the intraocular pressure.

Tonometry can be useful in identifying ocular hypertension (OHT – raised pressure in the eye), which is a risk factor for chronic open-angle glaucoma.

Other forms of tonometry might be used that measure eye pressure differently, for example by using drops and a probe.

Visual field test

You will be shown a sequence of light spots and asked which ones you can see.

Some dots will appear in your peripheral vision, which is where glaucoma begins.

If you can’t see the spots in your peripheral vision, it may indicate the glaucoma has damaged your vision.

Digital retinal photography

This involves taking a picture of your eye with a specialist camera that gives the optician a good view of the retina and your optic nerve at the back of the eye.

Your optician will pay special attention to the optic nerve, as that’s typically where glaucoma presents itself.

The images from your previous visits are compared against the current appearance of the eye to check for any changes that may indicate glaucoma.

Optic nerve assessment

Your optic nerve connects your eye to your brain. This can be assessed in a variety of ways during your examination and it is also photographed using a retinal camera.

Digital retinal photography (DRP) captures an image of your optic nerve which can be used as reference for future visits and to track any changes that may occur over time.

OCT (Optical Coherence Tomography)

OCT scans are similar to MRI and ultrasound scans and can help our opticians detect signs of glaucoma and other conditions up to four years earlier than more traditional imaging methods. Early detection means that treatment with prescribed eye drops, laser treatment or surgery can be started before you experience any significant sight loss.

How does optical coherence tomography work?

Much like an ultrasound scan uses sound waves, OCT uses light waves to take thousands of images of your retina, the layer of nerve fibres at the back of the eye. In order to carry out an OCT scan, you’ll be asked to sit with your chin on a support in front of a compact machine. The equipment will scan your eye without touching it. You will need to look at a light inside the machine, and you may see a flash of light.

The test is carried out on both eyes, one at a time. Overall, scanning takes just a few minutes. You may feel a little dazzled for a few moments after the test, but this will quickly pass — this is completely normal and is similar to what happens after having your photo taken with a bright camera flash.

What is optical coherence tomography used for?

While your first OCT scan can pick up signs of glaucoma, for most people this first test will provide baseline data about what your eye looks like when it’s healthy.

The clever thing about OCT is that it can pick up subtle changes in the thickness of the nerve fibre layers over time, giving your optometrist information that may indicate very early signs of conditions like glaucoma.

By repeating the OCT scan at every eye test, your optometrist can see if the nerve fibre thickness is changing outside of the normal age-related levels and can take action if it is.

Understanding gonioscopy: how can it diagnose glaucoma?

Gonioscopy refers to one of the tests an ophthalmologist will use to determine whether you have glaucoma and, if so, which type. Here, you’ll find information on the gonioscopy test, so you can feel reassured and comfortable if or when you have one.

What is gonioscopy?

During the test, an ophthalmologist uses a lens which is placed in contact with your eye to assess the health of the angle where fluid drains from your eye. The lens is able to do this because it incorporates mirrors and a prism which bends light, giving the ophthalmologist a clear view.

What happens during gonioscopy?

Gonioscopy is used to view the angle at the place where the coloured part of your eye (your iris) joins the cornea (the clear layer at the front of your eye).

The reason why it’s important to assess this angle, and how wide it is, is because this is where fluid drains out of your eye, and the balance of fluid pressure inside the eye is crucial in diagnosing, managing and treating glaucoma.

During your visit to the hospital, your ophthalmologist will ask you to place your chin on the rest of a slit lamp, which is a microscope designed to examine the front of your eye.

You’ll then be given some anaesthetic eye drops before the gonioscopy lens is placed on the front surface of your eye. The light from the slit lamp, shining through the gonioscopy lens, will allow the eye doctor to assess the drainage angle.

How corneal thickness can help diagnose glaucoma

How does corneal thickness affect glaucoma?

Intraocular pressure measurement can be affected by the thickness of the cornea. During the tonometry test, a small amount of pressure is applied to the cornea, and any resistance to the pressure helps measure IOP. A thick cornea may not ‘give’ as easily when pressure is applied, giving the impression of a high IOP. Similarly, a thin cornea may ‘give’ more than usual, which can give an impression of an abnormally low IOP.

What is the normal thickness of the cornea?

A normal range of corneal thickness is between 540µm and 560µm – µm represents measurements in micrometres, i.e. one-millionth of a metre. A thick cornea is 565µm or more, with a very thick cornea being greater than 600µm.

Typical corneal thickness can vary by race, with African-Caribbean people typically having a thinner cornea. For anyone with a thinner cornea, the risk is that lower IOP readings will potentially result in an underestimation of the actual level of intraocular pressure (IOP).^{(9, 10, 11)}

This risk, if unrecognised, can lead to misdiagnosis. This makes it even more critical that the ophthalmologist has an overall picture of your eye health, including your optic disc appearance, your nerve fibre layers, and your visual field test results. Thankfully, technology now is incredibly advanced, meaning glaucoma misdiagnosis is an extremely rare occurrence.

Should you be referred to an ophthalmologist due to being glaucoma suspect (showing signs and symptoms of the condition), the test your eye doctor will perform to measure corneal thickness is called a pachymetry test.

What is a pachymetry test?

The pachymetry test is a procedure used to measure central corneal thickness (CCT) and determine if it could be affecting the accuracy of your IOP measurements. A pachymeter can use light or ultrasound to assess the thickness of your cornea.

Optic Disc Cupping

The optic disc is the area where specific nerve fibres exit the retina to form the optic nerve. It is also where blood vessels enter the eye. The optic disc is usually round or oval in shape and is made up of two main parts: the outer rim and the cup. The outer rim tends to be orange or pink in colour and contains nerve fibres. The cup (in the centre) is a pit where there are no nerve fibres — this pit is where blood vessels enter the eye.

In people with glaucoma, elevated pressure in the eye can affect the optic disc, specifically the nerve fibres found within it.

What is optic disc cupping?

Optic disc cupping refers to the cup appearing to become larger over time, often due to fibres in the optic nerve dying. As the structural support for the optic disc is no longer there, the cup seems larger.

Increased pressure in the eye from glaucoma can cut off the blood flow to the optic nerve, which can eventually lead to the ‘death’ of optic nerve fibres in the outer rim of the optic disc.

Over time, more nerve fibres ‘die’ in the rim, leading to less structural support to the cup, this makes the central cup appear larger in comparison, which is what we refer to as optic disc cupping.

The initial size of the optic cup varies from person to person and it is perfectly possible for someone to have a naturally large optic cup without ever developing glaucoma.⁹ It is only when the cup size increases (i.e. optic disc cupping) that there could be a cause for concern.

How can you tell if you have optic disc cupping?

The cup-to-disc ratio (or CDR) is the measurement most commonly used by optometrists to assess the extent of optic disc cupping. It compares the diameter of the optic cup with the total diameter of the optic disc. A typical cup-to-disc ratio would often be about 0.3.10

A CDR higher than this does not necessarily mean that you have optic disc cupping, however. Having a larger optic cup can occur due to hereditary factors and a large optic disc can happen with or without optic nerve damage.

Usually, people with an overall larger optic disc will have a larger optic cup. So, even if your CDR is higher than 0.3-0.5 this does not necessarily mean that you have optic disc cupping.

Your cup-to-disc ratio progression, as well as the results from other tests such as optical coherence tomography (OCT), tonometry and visual fields, is what would be used by your ophthalmologist to help diagnose glaucoma.

How is optic disc cupping progression used to diagnose glaucoma?

While cupping alone is not enough to positively diagnose glaucoma, tracking its progression can be a useful tool for glaucoma diagnosis.11

Over time, measuring changes in the eye’s cup-to-disc ratio, as well as now using OCT to even more effectively monitor the optic disc and cup with 3D analysis, can be used to track and diagnose the degeneration of optic nerve fibres caused by glaucoma.

During your normal eye check, your optometrist may use what is called a slit lamp, along with a special magnifying lens, to have a look at the inside of your eye.

As the optic disc and cup have height and depth, using examination techniques that allow for a 3D analysis of the eye is very important in accurately detecting changes.

Another way that your optometrist can check for progression in optic disc cupping is by comparing the optic cup of each eye.

If one eye has a significantly larger CDR, this could indicate some potential loss of nerve fibres, which could be a sign of glaucoma.

Over time, if the CDR continues to increase, this is usually enough to inform a glaucoma diagnosis. The larger the cup appears and the greater the CDR, the more at risk patients are of developing chronic open-angle glaucoma.

How can optic disc cupping affect your vision?

As optic disc cupping progresses, the loss of optic nerve fibres can begin to impact your vision — primarily affecting your peripheral vision.11

Since the loss of vision is very slow and gradual, the person affected may not notice it until significant peripheral vision has been lost.

Customer testimonial

For Alan, it was during his normal eye test at Specsavers that his opticians spotted the early signs of glaucoma.
Now, after a quick referral, he can manage his glaucoma and protect his sight with some daily eye drops.

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Our partners

We work closely with the charity Glaucoma UK to help raise awareness of glaucoma and avoid preventable sight loss caused by the disease.

Our collaborations have included specialist glaucoma training for Specsavers colleagues so our teams can help people with glaucoma manage their condition – specifically helping people use eye drops.

Glaucoma UK is the only charity specialising in glaucoma in the UK. Over 700,000 people in the UK have glaucoma. Half of them don’t know they have it. Glaucoma UK want to change this and end needless glaucoma sight loss. The charity:

Campaigns to raise awareness of glaucoma so it is detected early and can be treated
Supports people to live well with glaucoma
Funds sight-saving research.

Part of Glaucoma UK’s mission is to ensure that people with glaucoma receive the information, advice and support they need to manage their condition well. Therefore, they work closely with eye health professionals, including ophthalmologists (eye doctors), optometrists and ophthalmic nurses, for example to provide training and produce resources as well as involving them in the governance of Glaucoma UK. Glaucoma UK recently formally incorporated the UK and Éire Glaucoma Society, a society for professionals working in glaucoma, meaning even closer links between the charity and eye care professionals.

As a charity, they are reliant on the kindness and generosity of supporters.

Glaucoma UK provides services including:

A free telephone helpline (weekdays, 9.30am – 5.00pm – call 01233 64 81 70 or email helpline@glaucoma.uk)
Free information resources available on the website and through hospitals, opticians, and GP surgeries
Glaucoma support groups
Organising Glaucoma Awareness Week and supporting other campaigns to raise awareness of glaucoma and eye health
Working in partnership with UK and European organisations to prioritise eye health, vision and glaucoma. This includes other charities, professional bodies such as the Royal College of Ophthalmologists, and the DVLA.

Glaucoma UK also works jointly with the following organisations to provide research funding into the treatment, management, and detection of glaucoma:

Royal College of Ophthalmologists
College of Optometrists
Royal College of Nursing
Fight for Sight

Glaucoma treatment

Glaucoma can be treated but early detection is important. If left untreated, glaucoma can cause visual impairment and damage that cannot be reversed. But if it’s detected and treated early enough, further damage to vision can be minimised or prevented.

So regular eye tests are essential. You should have an eye test at least every two years or more frequently if advised by your optometrist. For example, they may suggest you have more frequent eye tests if you have a close relative with glaucoma, such as a parent, brother or sister.

If your optometrist suspects glaucoma, you will be referred to an ophthalmologist for further tests. If the ophthalmologist confirms a diagnosis of glaucoma, they will also be able to explain:

How far the condition has developed
How much damage the glaucoma has had on your eyes
What may have caused the glaucoma

They will then be able to advise on initial treatment which is either selective laser trabeculoplasty (SLT) or an eye drop used on a daily basis coupled with regular follow-up appointments, depending on which your ophthalmologist feels is most suitable to you.

Drops may be used to examine your eyes in a glaucoma appointment – these can temporarily affect your vision.

Please check when making the appointment if you will be able to drive immediately after the appointment.

When will treatment start? How long will it last?

Glaucoma is a lifelong disease that progresses slowly, and treatment usually begins soon after the diagnosis is made.

The recommended initial treatment for glaucoma is selective laser trabeculoplasty (SLT), which is more effective with slightly slower estimated progression rates than eye drops. In addition, SLT can delay the need for eye drops and reduce the chance of needing them at all.³¹

However, if you choose not to have 360° SLT or if laser treatment is not suitable due to other conditions, eye drop treatment may be recommended to you by your ophthalmologist. Treatment may be started in one eye first. This is typically the ‘worse’ eye, with the higher intraocular pressure, where a single drug may be tried to see if it works.

Eye drop installation technique will also be demonstrated to ensure you understand how to prescribe the medication. Later, your doctor may test different combinations of medications to find a solution that works best for you.

Regular follow-ups with your doctor are required while being treated with glaucoma eye drop medication. This helps your doctor to detect any progression of the disease promptly. If your vision is found to be worsening despite treatment, you may need an increased dose of your current medication or to change the medication that you’re taking. You may also be recommended for surgery. Stable patients are usually examined at three to six month intervals depending on the severity of the disease and the rate that it is progressing.⁽¹²⁾

Can glaucoma treatment affect cataracts?

Cataracts are not treated using medication, but eye drops for glaucoma can occasionally cause issues if you have cataracts. Some glaucoma eye drops make the pupil larger and can give someone with cataracts increased problems with glare. Other eye drops can make the pupil smaller, which allows less light into the eye – for someone who also has cataracts, this can cause a drop in the level of vision.

If you notice problems with glare, or with how much you can see, after starting eye drops for glaucoma, it’s important to talk to your ophthalmologist. If you have both conditions and need surgery, your ophthalmologist’s priority will be to control the glaucoma first, which may be with medication or surgery. If you need surgery for both glaucoma and cataracts, your ophthalmologist will advise whether it would be best to do both at the same time or one followed by the other.

Glaucoma eye drops

If you decide against SLT, your ophthalmologist will suggest using eye drops as a treatment. The purpose of the eye drops is to lower the eye pressure, either by reducing the amount of fluid (aqueous humour) that is produced or by helping it to drain better from the eye.

How do eye drops treat glaucoma?

This is dependent on the type of glaucoma. Some eye drops do both, and, sometimes, doctors can prescribe a combination of eye drops to reduce the risk of vision loss or to try and stop vision getting any worse. In addition to providing more effective treatment, another combination of eye drops may be given to reduce side effects.

How to administer eye drops for glaucoma?

It’s important that you administer the eye drops correctly for your glaucoma treatment correctly, to make sure the medication is fully effective. While the number of drops you use may vary depending on the medication you’ve been prescribed, the process for administering them is usually the same.

Firstly, you should make sure you face the ceiling when putting your drops in — you can do this by tilting your head right back, or it might be easier to administer your drops by lying down. When you have the eye drops ready and your head is tilted back, you can administer them, using as many the number of drops you’ve been as prescribed.

Once administered, you should then apply pressure to the inner corner of your eye, where the tear ducts are. Hold your finger there for several seconds after instilling putting the drops in. This ensures that the medication doesn’t not drain away by the ducts, and allows the drops to be effective.

Types of eye drops used to treat glaucoma

Prostaglandin analogues

Prostaglandin analogues (PGAs) are usually the first type of glaucoma treatment recommended by doctors. This is because they are effective at reducing IOP, have an easy once-daily dosage, and minimal side effects.⁽¹³⁾

What are prostaglandin analogues?

PGAs are a synthetic version of the body’s natural compound, and come in the form of eye drops.

It’s the eye drop that binds to the receptor in order to stimulate the desired effect and help drain the fluid efficiently.

Types of prostaglandins used to treat glaucoma

Currently, there are four different types of prostaglandin analogue glaucoma eye drops available for glaucoma treatment in the UK:

Latanoprost
Travoprost
Bimatoprost
Tafluprost

Typically, these medications are used to help reduce IOP in people with open-angle glaucoma or ocular hypertension.

Latanoprost was the first PGA eye drop developed to lower IOP, and remains the most commonly prescribed.

Are there any common side effects for PGAs?

Generally, all of the PGAs mentioned above share some common side effects, however these tend to be localised to the eyes:

Dry eyes
Red (stinging) eyes
Increased pigmentation of the iris

It’s usually recommended that if you are pregnant or breastfeeding you do not take any PGAs for glaucoma treatment.^{(15,16,17,18)} If you are suffering from any side effects, contact your ophthalmologist as they will be able to analyse why you might be responding to a specific PGA in a certain way and can adjust your treatment plan accordingly.

Combination therapy with prostaglandin analogues

Although PGAs are considered the most effective class of drug for reducing IOP, they are frequently combined with other medications such as beta blockers, adrenergic agonists or carbonic anhydrase inhibitors for increasing the efficacy of treatment. Studies have shown that the fixed combinations are as effective as individual medications administered separately.⁽¹⁹⁾

More treatment options for glaucoma

Laser treatment

Depending on the type of glaucoma, different types of laser treatment can be effective. In an acute case, a procedure called an iridotomy is often used to quickly relieve the pressure and keep it lower. In non-acute cases, a selective laser trabeculoplasty (SLT) can be used to help lower the pressure – this is especially useful for people with open-angle glaucoma who have tried eye drops to lower the pressure, but they haven’t worked.

Selective Laser Trabeculoplasty (SLT)

A selective laser trabeculoplasty is usually recommended for people with open-angle glaucoma.⁽²²⁾In a laser procedure, SLT reduces intraocular pressure by increasing aqueous outflow through the trabecular meshwork. This, in turn, helps reduce intraocular pressure and prevent or slow down further vision loss in glaucoma patients.

SLT has minimal recovery time, is comparable to medical treatment, and can even delay or prevent the need for eye drops - thus avoiding the associated side-effects. Importantly, the effect of SLT is not permanent, but the procedure can be repeated.

Surgery

Selective Laser Trabeculoplasty (SLT) will be the first treatment offered to those with glaucoma, but surgery is an option. Trabeculectomy surgery helps to slow the development of glaucoma and lower eye pressure, many other procedures may be used depending on the stage and type of glaucoma.

Types of surgery

Trabeculectomy (tra·bec·u·lec·to·my) — this procedure involves creating a small flap in the sclera. The scleral opening is covered with a thin trapdoor that allows fluid to drain out of the eye, but also prevents it from draining too quickly.
Trabeculotomy (tra·bec·u·lo·to·my) — the procedure of choice in children with congenital glaucoma. This involves the removal of a small piece of tissue from the drainage angle in the eye to create an artificial opening. This allows fluid to drain out of the new opening, lowering the intraocular pressure.
Viscocanalostomy (vis·co·can·al·os·to·my) — involves the injection of a viscoelastic material into the eye. This injection dilates the canal and disrupts the layers of the trabecular meshwork. This procedure allows the fluid to slowly percolate out of the anterior chamber.
Deep sclerotomy (scler·o·to·my) — this is an innovative, minimally invasive surgical procedure for open-angle and juvenile glaucoma, which allows the intraocular pressure to be lowered without opening the anterior chamber or entering the eye. The procedure removes some of the tissue responsible for limiting the rate of aqueous outflow, which aims to allow more fluid to drain out of the eye. This, in turn, lowers eye pressure.
Trabecular stent bypass — involves the placement of a stent (tiny tube) to directly drain aqueous humour from the anterior chamber into Schlemm’s canal (a vessel in the eye that collects aqueous humour from the anterior chamber), thereby bypassing the obstruction at the level of the trabecular meshwork.

Recovery and aftercare following glaucoma surgery

The recovery time for invasive procedures can be several weeks and it’s advisable to keep water out of the eye during recovery. Patients should also avoid reading, bending, heavy lifting and driving for as long as advised by their ophthalmologist. The aftercare for each type of glaucoma surgery can be different, so you should always check with your ophthalmologist and follow their specific advice.

Here are some tips to ensure the best recovery⁽²³⁾:

Leave the padding/eye patch in place over the operated eye for the first day to prevent external injury
To prevent infection, keep your face clean and avoid touching the eye
Avoid using eye make-up for as long as directed
Avoid activities that expose the eye to water (for example, showering)
Wash your hands before using glaucoma eye drops
Use the postoperative antibiotic and anti-inflammatory eye drops as instructed
Protect the eye with goggles, especially in windy weather and during sports
Be alert for signs of postoperative complications (for example, sudden changes in vision, severe pain, redness, pus discharge, or halos around light bulbs)
Keep all your follow-up appointments

Secondary glaucoma treatment

Secondary glaucoma is when there is an identifiable reason for the pressure in your eye increasing, which has led to glaucoma developing. As with primary glaucoma (where we don’t know the cause), secondary glaucoma can be of the open-angle or angle-closure type, and can occur in one or both eyes.

Is secondary glaucoma curable?

The treatment plan for secondary glaucoma will usually depend on treating the underlying cause. However, your ophthalmologist may also recommend either medication such as glaucoma eye drops, laser treatment, conventional surgery or a combination of these to manage the glaucoma itself.

With that in mind, let’s explore the different kinds of secondary glaucoma, the treatment options available, and the most effective treatments for each type.

Types of treatment for secondary glaucoma:

Exfoliative glaucoma — Generally, medical therapy is not used to control this kind of glaucoma. Your ophthalmologist will usually recommend laser trabeculoplasty or incisional surgery.
Neovascular glaucoma — This is treated with medication, including beta blockers that reduce the production of aqueous humour (the fluid in your eye) and topical steroids that help manage the pain and inflammation.
Pigmentary glaucoma — Your ophthalmologist will focus on controlling your eye pressure. They will usually do this through a combination of eye-drop medications that reduce the production of fluid within the eye. Alternatively, lasers or incisional surgery may be used to unblock the drainage system in your eye.
Traumatic glaucoma — A doctor will customarily recommend incisional surgery in order to restore the intraocular structures, and corticosteroids and antibiotics may be immediately prescribed to prevent tissue scarring and infection. In some cases, it’s possible the patient may also need medication in the form of beta blockers and Diamox tablets post-surgery to maintain the intraocular pressure.
Uveitic glaucoma — While the focus will be on managing the underlying cause, especially in the case of auto-immune disorders, IOP is usually controlled using drainage shunts, lasers and a combination of drugs including beta blockers and carbonic anhydrase inhibitors. Treatment of uveitic glaucoma is usually complex, and your doctors will work closely with each other to devise a safe and effective treatment plan for you.
Congenital glaucoma — Microsurgery is used to correct the structural deficiencies which originated during the developmental period of the baby. This type of surgery is incredibly advanced, using small tools to create a drainage canal for any excess fluid in the eye. If necessary, the doctor will also implant a small drainage valve or tube which will carry the fluid out of the eye.

Carbonic anhydrase inhibitors

A group of enzymes called carbonic anhydrases are responsible for the secretion of aqueous humour, but sometimes they get carried away and produce too much fluid, causing a rise in intraocular pressure.

Carbonic anhydrase inhibitors are used to suppress the activity of carbonic anhydrase enzymes.

CAIs are available as eye drops as well as oral medication. The difference here often comes down to whether your glaucoma is already being controlled by eye drops.

Acute angle-closure glaucoma treatment

Treatment for acute ACG usually begins with topical eye drops and intravenous medication, both of which aim to reduce IOP and provide pain relief. The eye drops narrow the pupil, which lowers the amount of fluid your eye makes and helps to decrease pressure. Once the IOP has reduced a little, your ophthalmologist may discuss surgical options with you, for further treatment if necessary.

These are common medication types and treatments an ophthalmologist might recommend for acute angle-closure treatment:

Carbonic anhydrase inhibitors — If someone with acute ACG has an extremely high IOP, Diamox tablets (a common brand of Acetazolamide) is immediately administered.
Mannitol — Unless the patient has a contradictory health condition, such as kidney disease or dehydration, a Mannitol injection can be given intravenously to reduce the pressure. This diuretic works by decreasing vitreous volume (a clear, colourless fluid that fills the space between the lens and the retina), which ultimately prevents further build-up of IOP.
Osmotic agents — These can be given topically (such as an eye drop) or taken orally as a pill to help clear corneal swelling (swelling of the clear, protective outer layer of your eye) and bring down a severely high IOP.
Steroids — Steroids like prednisolone are often used in limited doses to reduce inflammation and pain. These are used sparingly, as steroids have been known to increase IOP.
Laser peripheral iridotomy —When the angle is partially or completely closed up, a laser is used to make small holes in the peripheral area of the iris to assist drainage of fluid. Your ophthalmologist may also recommend that the procedure be performed in the other eye as a pre-emptive measure.
Paracentesis —Manual drainage of eye fluid is usually only performed as a final measure to bring down IOP until the medication starts to take effect.
Filtration surgery — This would usually only happen if laser facilities are unavailable, and if damage to the optic nerve is significant.

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References

1. Ou, Y. (2017). Glaucoma and Diabetes. BrightFocus Foundation. [Online]. Available at: https://www.brightfocus.org/glaucoma/article/glaucoma-and-diabetes [Accessed 08 May 2019].

2. Mitchell, P., et al. (1997). Open-angle Glaucoma and Diabetes. Ophthalmology, 104(04). [Online]. Available at: https://www.aaojournal.org/article/S0161-6420(97)30247-4/pdf [Accessed 08 May 2019].

3. Klein, B., et al. (1994). Open-angle Glaucoma and Older-onset Diabetes. Ophthalmology, 101(07). [Online]. Available at: https://www.aaojournal.org/article/S0161-6420(94)31191-2/pdf [Accessed 08 May 2019].

4. Dielemans, I., et al. (1996). Primary Open-angle Glaucoma, Intraocular Pressure, and Diabetes Mellitus in the General Elderly Population. Ophthalmology, 103(08). [Online]. Available at: https://www.aaojournal.org/article/S0161-6420(96)30511-3/pdf [Accessed 08 May 2019].

5. Neilsen, NV. (1983). The prevalence of glaucoma and ocular hypertension in Type 1 and Type 2 diabetes mellitus. Acta Opthalmologica, 61(04). [Online]. Available at: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1755-3768.1983.tb04357.x [Accessed 08 May 2019].

6. https://nei.nih.gov/news/pressreleases/012114]

7. Stanford Children’s Health (no date). Childhood Glaucoma. [Online]. Available at: https://www.stanfordchildrens.org/en/topic/default?id=childhood-glaucoma-90-P02106 [Accessed 6 August 2019].

8. Johns Hopkins Medicine Wilmer Eye Institute (no date). Glaucoma FAQs. [Online]. Available here. [Accessed 29 August 2019].

9. Beutelspacher, SC., Serbecic, N., Scheuerle, AF. Assessment of central corneal thickness using OCT, ultrasound, optical low coherence reflectometry and Scheimpflug pachymetry. Eur J Ophthalmol. 2011 Mar-Apr;21(2):132-7.

10. William A. Argus MD Ocular Hypertension and Central Corneal Thickness Ophthalmology Volume 102, Issue 12, December 1995, Pages 1810-1812

11. Brandt, JD., Beiser, JA., Kass, MA., Gordon, MO., The Ocular Hypertension Treatment Study (OHTS) Group, Central corneal thickness in the ocular hypertension treatment study (OHTS) Ophthalmology Volume 108, Issue 10, October 2001, Pages 1779-1788

12. Parikh, RS., Parikh, SR., Navin, S., Arun, E., Thomas, R. Practical approach to medical management of glaucoma. Indian J Ophthalmol. 2008;56(3):223–230. [Online]. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2636120/ [Accessed 29 August 2019].

13. Winkler, NS. and Fautsch, MP. (2014). Effects of Prostaglandin Analogues on Aqueous Humor Outflow Pathways. Journal of Ocular Pharmacology and Therapeutics, 30(2-3), 102–109. doi:10.1089/jop.2013.0179Y

15. Pharmacia & Upjohn Inc. Xalatan (latanoprost) sterile ophthalmic solution 0.005% (50 mcg/mL) prescribing information. Kalamazoo, MI; 2003 Sep

16. Alcon Pharmaceuticals. Travatan (travoprost) ophthalmic solution 0.004% prescribing information. Fort Worth, TX; 2004 May.

17. https://www.drugs.com/sfx/bimatoprost-ophthalmic-side-effects.html

18. https://www.drugs.com/sfx/tafluprost-ophthalmic-side-effects.html

19. Aptel, F., Chiquet, C., and Romanet, J-P. (2012). Intraocular Pressure-Lowering Combination Therapies with Prostaglandin Analogues. Drugs, 72(10), 1355–1371.

20. Glaucoma UK. (no date). Types of glaucoma eye drops. [Online]. Available at: https://glaucoma.uk/about-glaucoma/treatments-surgery/eye-drops/ [Accessed 12 January 2021].

21. Glaucoma.org. (no date). Medication guide. [Online]. Available at: https://www.glaucoma.org/treatment/medication-guide.php [Accessed 22 May 2019].

22. Gazzard, G., et al. (2019). Selective laser trabeculoplasty versus eye drops for first-line treatment of ocular hypertension and glaucoma (LiGHT): a multicentre randomised controlled trial. [Internet]. The Lancet. [Online]. Available at: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)32213-X/fulltext [Accessed 7 November 2019].

23. Kyari, F. and Abdull, MM. (2016). The basics of good postoperative care after glaucoma surgery. Community Eye Health Journal. Volume 29 (94); 2016. [Online]. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5100471/ [Accessed 12 August 2019].

What is glaucoma?

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Types of glaucoma

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Developmental glaucoma

Myocilin mutations

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Visual symptoms of glaucoma

Diagnosing glaucoma

Tests for glaucoma

Eye pressure test (tonometry)

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Optic nerve assessment

OCT (Optical Coherence Tomography)

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Understanding gonioscopy: how can it diagnose glaucoma?

What is gonioscopy?

What happens during gonioscopy?

How corneal thickness can help diagnose glaucoma

How does corneal thickness affect glaucoma?

What is the normal thickness of the cornea?

Optic Disc Cupping

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Glaucoma treatment

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Prostaglandin analogues

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Combination therapy with prostaglandin analogues

Alpha-adrenergic agonists

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More treatment options for glaucoma

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Selective Laser Trabeculoplasty (SLT)

Surgery

Types of surgery

Recovery and aftercare following glaucoma surgery

Secondary glaucoma treatment

Is secondary glaucoma curable?

Types of treatment for secondary glaucoma:

Carbonic anhydrase inhibitors

Acute angle-closure glaucoma treatment

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