Glaucoma, often called the “silent thief of sight,” is a group of eye diseases that damage the optic nerve, leading to gradual vision loss if left undiagnosed and untreated. Awareness and knowledge about glaucoma are therefore important, as around 1-2% of the global population suffers from it.
Glaucoma can affect anyone, with prevalence increasing significantly with age (up to 10% in people over 90) and higher rates in certain ethnic groups like those of African descent. This makes it a leading cause of irreversible blindness worldwide, impacting around 80 million people today.
What is Glaucoma?
Glaucoma refers to a group of eye diseases in which the optic nerve is irreversibly damaged. In most cases, this is due to increased eye pressure. The optic nerve transfers visual information from the eye to the brain and if it’s damaged, it can result in visual disturbances that restrict the field of vision, and even blindness.
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What Causes Glaucoma?
The eye produces a fluid called aqueous humor that nourishes eye tissues and drains through a mesh-like structure. Normally, this fluid drains away through a mesh as more fluid is made. That way, the pressure in the eye always stays the same. In glaucoma, the mesh (which is technically called the ‘trabecular meshwork’) gets slightly blocked, and the fluid can’t drain away properly. This results in a buildup of pressure. The reason why the trabecular meshwork becomes blocked isn’t always apparent. Often it is simply age-related.
The increased pressure in the eye can damage nerve fibres. These run from the retina, and damage can occur at the point where they meet (converge) to become the optic nerve (known as the optic nerve head or optic disc). The optic nerve is the main nerve of sight. These damaged fibres result in permanent patches of visual loss. In some cases, this can eventually lead to total loss of vision (severe sight impairment or blindness).
Glaucoma can affect both eyes. However, it can often progress more quickly in one eye than in the other.
What Are Early Symptoms of Glaucoma?
Symptoms depend on the type of glaucoma you are suffering from. Most people notice no early signs because peripheral (side) vision loss happens gradually and unnoticed. Some glaucoma types often go undetected until advanced stages, with subtle blind spots near the nose. Other types may bring sudden severe eye pain, headaches, blurred vision, halos around lights, red eyes, nausea, and vomiting—seek emergency care immediately.
What Types of Glaucoma Are Known?
There are three main types of glaucoma: primary, secondary, and developmental (glaucoma in babies and children).
Primary Glaucoma
Primary glaucoma is the most common type of glaucoma and can be split into two main types: Primary Open Angle Glaucoma (POAG) and Primary Angle Closure Glaucoma (PACG).
Primary open angle glaucoma (POAG)
Primary open angle glaucoma (POAG), also known as ‘chronic open angle glaucoma’ or just ‘open angle glaucoma’, is the most common form of glaucoma. POAG is a slow-developing disease that causes damage to the optic nerve and is often symptomless, especially in the early stage.
The trabecular meshwork, through which the fluid in your eyes drains away, is found in the angle between the cornea and the iris (often called the drainage angle). In most cases of POAG, the problem occurs due to the fluid outflow not working as well as it should. The eye can’t get rid of the fluid fast enough and the build-up results in increased eye pressure. The increase in pressure damages the optic nerve by reducing the amount of blood that can get through the tiny blood vessels and by pressing on the nerve itself.
Who is at risk of primary angle closure glaucoma?
Family history – POAG often runs in families. As a rough guide, your brothers, sisters and children may be up to 10 times more likely to develop primary open angle glaucoma.
Ethnicity – People of African-Caribbean origin are more likely to develop primary open angle glaucoma. They’re also likely to develop it at a younger age.
Short sight – People with short sight (myopia) are more likely to have primary open angle glaucoma.
Symptoms of primary open angle glaucoma (POAG)
POAG gives no warning symptoms in its early stages. There is no pain and, in many cases, a person with this condition is completely unaware of the damage that is being done. This is because the typical damage occurs in the off-centre (peripheral) parts of the vision. Both eyes work together and one eye ‘fills in’ for the other so that blank patches are not noticed.
Treating primary open angle glaucoma
The aim of treating POAG is to reduce the pressure within the eye. By achieving this, it reduces pressure on the optic nerve and helps to stop further damage. Treatment is usually by eye drops. These help by reducing the fluid produced by the eye, increasing the drainage of fluid from the eye or both.
Laser is another common treatment and may be offered instead of, or in addition to eye drops.
If eye drops/ laser do not lower the eye pressure enough, surgical treatments are available.
Primary angle closure glaucoma (PACG)
Primary angle closure glaucoma (PACG) is less common but like POAG, is due to fluid being unable to drain away from the eye properly. The main difference between primary angle closure and primary open angle glaucoma is that PACG is more closely connected with the shape of the eye, and how it sits in the eye socket, whereas POAG is related to the drainage systems not working as effectively as they should.
Both PACG and POAG lead to an increase in eye pressure. The increase in pressure damages the optic nerve by reducing the amount of blood that can get through the tiny blood vessels and by pressing on the nerve itself.
Some eyes naturally have a narrower drainage angle for example, people with smaller eyes, people who are long-sighted or people of particular ethnic origins. This smaller angle can slow down, or even close completely causing fluid to build up and eye pressure to rise.
PACG can be chronic or acute. Chronic angle closure develops slowly, usually without symptoms, as the drainage angle gets smaller and the eye pressure slowly rises. This is usually identified during a routine eye test at an optometrist. The eye doctor may use laser treatment to help prevent the narrow angle closing completely.
Who is at risk of primary angle closure glaucoma?
Age – Primary angle closure glaucoma gets more common with age.
Family history – Glaucoma often runs in families. As a rough guide, your brothers, sisters and children are around four times more likely than other people to develop primary angle closure.
Ethnicity – People of east Asian origin are more likely to develop primary angle closure glaucoma.
Gender – Women are around one and a half times more likely than men to develop primary angle closure.
Long sight – People with long sight are more likely to have primary angle closure.
Symptoms of primary angle closure glaucoma
Acute primary angle closure, also known as ‘acute glaucoma’ or ‘acute angle closure glaucoma’, happens when a blockage is sudden and causes the pressure to rise very high, very quickly. Symptoms include intense pain, redness of the eye, blurred or reduced vision, headache and nausea. This tends to be very painful, and it is vital that you seek medical advice immediately, as this sudden rise in eye pressure can cause permanent damage to your sight.
Sometimes, people get a series of mild attacks of angle closure. These are called ‘sub-acute’ attacks. Symptoms may include blurred vision, halos around lights and headaches. These attacks may come and go, but if this happens, it’s very important to seek immediate medical advice as it might be a warning of a future serious attack.
If you have narrow angles (where the cornea and iris meet), and are therefore at greater risk of developing PACG, this will be identified at a routine eye test.
Treating primary angle closure glaucoma
Acute angle closure is initially treated with drops and an intravenous injection to lower the eye pressure. Once the pressure is lowered, a laser or surgical procedure is carried out in order to bypass the blockage in your eye’s drainage system and prevent it happening again.
Normally, the same procedure is also performed in the other eye in order to prevent an attack of acute angle closure in that eye. These treatments are not painful and are usually carried out as an out-patient, although a short stay in hospital may occasionally be required.
If primary angle closure is diagnosed and treated without delay, there may be an almost complete and permanent restoration of vision. However, any delay in addressing the problem may result in permanent damage to the affected eye. Occasionally the pressure may remain raised and ongoing treatment will be required.
Chronic angle closure glaucoma is treated in a similar way with drops to lower the pressure. In addition, laser treatment is often given to prevent further angle closure.
Secondary Glaucoma
Secondary glaucoma is the name used to describe glaucoma that occur as a side effect or “secondary” to another underlying medical condition or trauma. This differs from primary glaucoma, where there’s no identifiable cause for the glaucoma to develop. Even though the cause of primary and secondary glaucoma may be different, the increase in eye pressure and the resulting damage to the optic nerve are the same.
Causes of secondary glaucoma
Secondary ocular hypertension (or OHT) is when the eye pressure measurement is higher than the normal range but there is no detectable damage to the optic nerve. It can occur following disease or surgery on the cornea. The cornea is the clear window at the front of the eye. Corneal infections (viral or bacterial) or corneal burns can cause inflammation leading to raised eye pressure. Many corneal conditions require the use of long-term steroid eye drops which can also result in increased eye pressure (see below).
Iatrogenic glaucoma literally means ‘caused by a doctor’ and unfortunately this is one of the most common reasons people experience secondary rises in eye pressure. The main iatrogenic cause is following retinal surgery. During retinal surgery, the surgeon may need to put gas or silicone oil in the eye. These substances can have the side effect of raising the eye pressure.
Medicine-related secondary glaucoma is the result of inflammation caused by medication, typically steroids. Steroids are used for a variety of medical conditions and can be inhaled (inhalers), taken orally as tablets, injected or applied directly to the skin or eye. They are an important type of medicine, but a possible side effect is increased eye pressure. This effect is called ‘steroid response’. This is most common when the steroids are applied locally to the eye, for example when treating uveitis. In most cases of ‘steroid response’, eye pressure will fall back to normal levels when you stop taking the steroids. It is important to have regular eye pressure checks if you are using steroid eye drops for a long time. But don’t reduce or stop steroid medication without prior talking to your doctor!
Lens-related issues, like cataracts, can also cause a secondary rise in eye pressure. An advanced cataract can swell up and block the flow of aqueous through the pupil and out of the eye. Removing the cataract relives this.
Neovascular (“new blood vessels”) glaucoma occurs when poor blood supply within the eye causes new blood vessels to grow on the surface of the eye and into the drainage channel. The new blood vessels can cause eye pressure to rise by blocking the outflow of aqueous. This type of glaucoma is usually associated with other eye conditions like diabetic retinopathy.
Pigment dispersion syndrome and pseudoexfoliation syndrome are two of the most common secondary open angle glaucoma. Pigment dispersion and pseudoexfoliation are often grouped together as they both result in blockage of the trabecular meshwork (drainage channels) by materials that are naturally present in the eye.
Pigment dispersion syndrome occurs when the pigment granules in the iris (the coloured part of your eye) break away and clog up the trabecular meshwork. If the trabecular meshwork is blocked, it is almost impossible for the aqueous to drain effectively and this results in increased eye pressure. This puts extra pressure on the optic nerve and can result in damage to vision. This condition is more common in young, short-sighted men.
In pseudoexfoliation syndrome, deposits of protein form in the eyes. These deposits look like dandruff on the front of the lens, the iris, around the edges of the pupil and in the drainage channels. As the iris moves and the lens and iris touch, deposits flake off the lens and into the aqueous fluid. These flakes can clog the trabecular meshwork. This can prevent aqueous draining away, leading to increased eye pressure and damage to the optic nerve. This condition is more common in older people and in people of Scandinavian and Southern Mediterranean origin.
Trauma induced glaucoma can mean either a blow to the eye, a penetrating injury (when something pierces the eye) or a chemical injury (such as an alkali burn) may result in glaucoma. It can happen immediately after the injury or develop over time. Blunt trauma (such as a blow to the eye) can affect the shape of the eye, meaning the pressure builds up over several years. People affected will need to be monitored to limit the chance of developing glaucoma in the future.
Uveitis induced glaucoma may occur when a part of the eye called the uvea becomes swollen and inflamed. If uveitis leads to increased pressure, which then causes damage to the optic nerve, it is called uveitic glaucoma.
Secondary ocular hypertension, or increased eye pressure can occur following disease or surgery on the cornea. The cornea is the clear window at the front of the eye. Corneal infections (viral or bacterial) or corneal burns can cause inflammation leading to raised eye pressure. Many corneal conditions require the use of long-term steroid eye drops which can result in increased eye pressure.
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Childhood Glaucoma
Childhood glaucoma is rare. About one in 10,000 children are born with glaucoma or develop it in childhood. In most cases, it is discovered before the child’s first birthday.
Types of glaucoma in children
Primary congenital glaucoma
The most common glaucoma in babies and small children is Primary congenital glaucoma. It occurs when the eye hasn’t developed properly in the womb and this leads to issues with the flow of aqueous fluid out of the eye. If the fluid is unable to drain effectively, it builds up inside the eye and causes the eye pressure to rise. This causes stress to the optic nerve and may lead to permanent damage to vision. Glaucoma of this type tend to run in families.
Secondary glaucoma in children
Secondary glaucoma in babies and children is the result of an injury or another condition. These include Axenfeld-Rieger’s Anomaly, where there may be developmental issues with various parts of the eye and Peter’s Anomaly where there are abnormal developments in the lens and cornea.
Glaucoma often follows cataract surgery in babies and young children. Cataract surgery replaces the lens in the eye if it has become cloudy, but the reason for the development of glaucoma after cataract surgery is still not well understood.
Glaucoma can also occur if the eye becomes inflamed for any reason, such as in children who have a childhood form of arthritis, as the drainage channels may get blocked with inflammatory cells.
Glaucoma can sometimes occur in children with other conditions such as aniridia, in which there is no, or very little, development of the iris. Glaucoma can also occur in Sturge-Weber syndrome; people with Sturge-Weber syndrome have a blood vessel birth mark on the face, often on the forehead. Children with these signs will need to be monitored for the development of glaucoma.
How is Glaucoma Diagnosed?
Puff tonometry
The test for the pressure in your eye is quick and easy. It sometimes involves blowing a puff of air at your eye with a special piece of equipment. This is called puff tonometry.
Goldmann’s tonometer
The other, slightly more accurate, way is by gently touching your eye with a pressure-measurer called a Goldmann’s tonometer. Either way, it doesn’t hurt and only takes a few seconds.
Field of vision test
This test is essentially measuring how much of the world around you can see whilst you are looking directly forwards. Glaucoma affects the outside (periphery) of your field of vision first.
Slit lamp
To look at the back of your eye, at the optic disc and retina, is slightly more in depth.
Cornea thickness test (pachymetry)
The thickness of your cornea may also be measured. This is because the thickness of your cornea can affect your intraocular pressure reading.
Gonioscopy
A special lens may also be used to examine the drainage area (or trabecular meshwork area) of your eye. This quite specialized examination is called gonioscopy.
How is Glaucoma treated?
Treatment of glaucoma depends on the type of glaucoma you are suffering from.
The main aim of treatment for glaucoma is to lower your eye pressure. If your eye pressure is lowered, further damage to the optic nerve is likely to be prevented or delayed.
The target eye pressure varies from case to case. It partly depends on how high your original pressure is. Your eye specialist will advise. Eye pressure can be lowered in various ways.
Eye drops for Glaucoma
A variety of eye drops can lower eye pressure and are often the first treatment option recommended. They may aim to:
- Increase the drainage of aqueous humor (for example, prostaglandin analogue drops).
- Reduce the amount of aqueous humor that you make (for example, beta-blockers, carbonic anhydrase inhibitors and adrenergic agents).
The treatment you will usually be offered first is a type of prostaglandin analogue drops. Your doctor will show you how to put the drops in properly, and watch you putting them in, the first time you use them.
Some drops work better in some people than in others. Some drops are not suitable for some people. For example, beta-blocker drops may not be suitable if you have asthma or heart disease. The possible side-effects vary between the different types of drops. So, if the first does not work so well, or does not suit, another may work fine. In some cases, two different types of drops are needed to keep the eye pressure low. Preservative-free eye drops are available if you find you are allergic to preservatives added to the drops.
It is vital to use your drops exactly as instructed. If you are unsure whether you are using your drops correctly, ask for advice from your doctor or practice nurse. An eye specialist will keep a regular check on your eye pressures, optic nerves and field of vision. How often you need to be followed up will depend on your particular situation.
Laser treatments for Glaucoma
If you have ocular hypertension or glaucoma, you may be offered a form of laser surgery called laser trabeculoplasty (SLT).
A laser can make tiny holes in the trabecular meshwork, which improves the drainage of the aqueous humor. This treatment only takes a few minutes and is done under local anesthetic. A special contact lens is put on your eye to help the specialist focus the laser beam. You may feel a pricking sensation and notice some flashing lights, but the procedure is usually well tolerated.
Having this surgery can delay the need for eye drops. In some but not all cases, it can mean you will not need to use regular eye drops in the future. Sometimes a second laser procedure will be needed later if your pressure starts to increase again. Complications from this surgery are uncommon, but your surgeon will explain these to you before you consent to treatment.
Surgery for Glaucoma
If other glaucoma treatments are not effective, an operation called trabeculectomy is an option. This involves creating a channel from just inside the front of your eye to just under your conjunctiva. By this route the aqueous humor can bypass the blocked trabecular meshwork. In effect, it is like forming a small safety valve for the aqueous humor. Surgery may be advised if a trial of eye drops has failed to achieve target eye pressures, especially in younger people, or if you have very high eye pressures.
As with all operations, there is a small risk of complications. Also, the operation may have to be repeated in some cases. This is usually because some scar tissue forms at the site of the channel and prevents it working to drain the aqueous humor.
Rarely, a tiny drainage tube may be inserted into your eye to drain the aqueous humor. This is usually only carried out if trabeculectomy has been tried a number of times and has been unsuccessful.
What Can I Do Myself Against Glaucoma?
The first most important step is to visit an ophthalmologist and get a clear diagnosis. Follow the recommendation, take the prescribed medicine, and follow up with the regular controls.
Additionally, patients may receive short answers or generalized guidance such as, “Eat healthy, exercise regularly, and try to relax.” What does that mean practically? Some general wellness principles can be adopted by glaucoma patients looking to optimize their health.
Physical Health Recommendation for Glaucoma Patients
Patients with glaucoma should strive to follow three key physical recommendations:
Keep your head above your heart: Patients with glaucoma should avoid exercises during which their head is below their heart, such as the downward dog yoga pose and headstands.
Avoid sustained Valsalva maneuvers: Forceful exhalation against a closed airway (Valsalva maneuver) can increase pressure in the eye. Patients with advanced glaucoma or with a high risk of progression should steer clear of lifting heavy weights, playing wind instruments such as the saxophone or the didgeridoo, straining to defecate, etc.
Perform aerobic exercise: Any type of cardiovascular activity—jogging, biking, tennis, pickle ball, etc.—is beneficial not only for eye health but also for overall health.
Nutritional Health Recommendation for Glaucoma Patients
Some dietary modifications can help optimize health for glaucoma and in general.
To Consume:
Flavonoids have been shown to prevent glaucomatous progression and increase blood flow to the optic nerve, making them ideal for patients with glaucoma. These chemicals are found in fruits and vegetables, especially red and purple produce such as berries, red onions, and radishes. Other foods rich in flavonoids include legumes, lentils, chickpeas, caffeinated teas, and dark chocolate.
Another valuable dietary component for patients with glaucoma is nitric oxide (NO). Studies have shown that NO may play a role in the regulation of IOP by increasing outflow. NO can be found in dark, leafy green vegetables such as spinach and kale as well as in celery, beets, citrus, eggplant, and dark chocolate.
Patients with glaucoma can also consider regular consumption of omega-3, especially docosahexaenoic and eicosapentaenoic acids. These fatty acids can be found in walnuts, seafood (eg, wild salmon, tuna, sardines, oysters), and sea algae.
To Avoid:
Saturated fats, trans fats, and complex carbohydrates have been shown to decrease blood flow and build plaque on the arteries. In general, individuals should monitor their consumption of red meat, processed meats, dairy products, fried foods, potatoes, bread, rice, and pasta.
A big point of discussion regarding healthy habits for glaucoma has centered on the consumption of coffee. The research is conflicting: Coffee has been shown to increase eye pressure in the short term, but it also provides the benefit of increased blood flow. One or two cups of coffee per day is likely acceptable, but patients with severe glaucoma may want to limit their caffeine intake.
Environmental Health Recommendation for Glaucoma Patients
Smoking is a concern for both eye and general health. Cigarettes and cigars contain nicotine, which is associated with elevated eye pressure. Secondhand smoke exposure can produce harmful effects as well, the same is true for vaping and chewing tobacco. In addition, smoking can cause irritation and dry eye. Patients with glaucoma may already experience these side effects from their eye drops, and smoking may exacerbate the problem.
Long-term lead exposure may be a risk factor for glaucoma. Patients who work or have worked in industries such as painting, toy making, furniture building, jewelry making, cosmetics, food, and plumbing may consider undergoing a blood test to evaluate potential lead exposure.
Mental Health Recommendation for Glaucoma Patients
Mental and emotional well-being are important considerations. Studies of stress and glaucoma are lacking, but evidence suggests that stress and anxiety can increase heart rate and eye pressure. Further, the stress hormone cortisol is known to increase eye pressure. Yoga, breathing exercises, and meditation may all help to increase blood flow and decrease eye pressure.
With TheknowHow- Second opinion medical, Your Health Matters!
Your health matters—especially your sight, which no one should take for granted. Glaucoma may be silent, but with regular eye exams, early detection, and simple lifestyle steps like protecting your eyes from injury and managing health conditions, you can take control. Prioritize your vision today; schedule that check-up and spread awareness to keep the “thief of sight” at bay.
A contribution by Dr. Gabriele Stumm,
Screen Time and Glaucoma
Staring at screens for long time near to your eyes (especially smartphones) may rise eye pressure on short time. While it is not thought to be a cause of glaucoma, it is not a good companion. Therefore, stick to
20-20-20 Rule: Every 20 minutes, look at something 20 feet away for 20 seconds.
Blink Often: blink fully and frequently to keep eyes moist.
Stay Hydrated & Lubricate: Drink water and use artificial tears if eyes feel dry.
Take Breaks: Get up and move away from screens regularly.
Consider Screen Position: Maintain proper distance and avoid low-light environments while using devices (social media watching in bed…).
