Glaucoma Symptoms and Treatment

Glaucoma, a common eye condition, often begins with no symptoms, which means it can be hard to detect. As the condition develops, it is likely to be accompanied by symptoms such as blurred vision, rainbow-coloured circles around lights, and other symptoms depending on the type of glaucoma and its cause.1

As glaucoma is the leading cause of blindness when left untreated, it is important to know your symptoms, treatment options, and how to seek medical advice at the right time.2 Read on to find out more.

What is Glaucoma and what are the causes?

Glaucoma is a group of eye conditions that damage the optic nerve by increasing the intraocular pressure: the pressure inside the eye.2 This increase in pressure can damage the blood vessels that supply the eye with blood. 

The intraocular pressure increases due to a build-up of eye fluid called aqueous humour, which usually flows through a drainage system called the trabecular meshwork that works similarly to a sieve. When this system cannot work properly, or there is a blockage, the fluid builds up in the eye, and intraocular pressure increases and causes neural damage.3

Glaucoma can also be caused by underlying eye conditions such as uveitis, which is an inflammation of the eye. Other causes include diabetes or specific prescribed medications.1

Types of Glaucoma and risk factors

It is unclear as to why glaucoma develops in some people and not others; however, the most common risk factors are:

  • Age: As you get older, your risk of developing glaucoma increases
  • Medical conditions: diabetes can increase your risk of glaucoma
  • Family History: If glaucoma is already present in a close relative, you are at an increased risk
  • Ethnicity: There is evidence to suggest those of African or Asian origin are at a higher risk of developing glaucoma1
  • Taking systemic or topical corticosteroids

Interestingly, there is a 4 to 1 ratio of angle-closure glaucoma cases in people assigned female at birth vs people assigned male at birth.7

Glaucomas are often classified into two main categories listed below.

Primary open-angle Glaucoma

Open-angle glaucoma is caused by the drainage channels in the eye becoming blocked over time. There are two subcategories within this: High tension glaucoma and normal tension glaucoma.

Often called primary glaucoma, this is the most common form of glaucoma, with up to 80% of cases in this form.3 The ‘open angle’ part of the name is derived from the angle where the iris meets the cornea. In this case, the angle is wide and open.5 

Acute angle-closure Glaucoma

This is a very rare form of glaucoma, caused by the drainage channels in the eye becoming suddenly blocked; consequently, the pressure inside the eye increases very quickly.

For this type of glaucoma, the ‘angle-closure’ refers to a narrow or even closed angle between the iris and cornea.5 This means that the intraocular pressure suddenly increases and leads to severe symptoms and damage, requiring immediate medical attention.

Other Glaucomas

Aside from these two types, other types of glaucoma include:

  • Childhood (congenital) glaucoma - caused by eye abnormalities present from birth.
  • Secondary glaucoma - caused by underlying eye conditions (uveitis), topical or systemic corticosteroids, and eye injuries.4

Symptoms of Glaucoma

The symptoms only appear after the patient has been suffering from the condition for a long period of time. When symptoms are eventually experienced, they can interfere with your quality of life, restricting activities such as driving. Symptoms of the two main forms of glaucoma are listed below; however, these symptoms are not exclusively limited to these two forms.

Symptoms of open-angle glaucoma

This type of glaucoma develops so slowly that it goes unnoticed, as vision loss is concentrated in the periphery, and by the time symptoms are experienced, damage to the optic nerve is serious.6 

Symptoms include:

  • Redness of the eye
  • Reduced peripheral vision/loss of vision
  • Changes to how your pupil dilates
  • Symptoms of acute angle-closure glaucoma

For this rarer form of glaucoma, the ‘angle-closure’ causes the symptoms experienced. This is because the iris bulges during pupillary blockage when the pupils increasingly dilate. The iris bulging closes the angle between the iris and cornea, preventing the outflow of the aqueous humour and increasing intraocular pressure.7 

As this process happens so quickly, the symptoms are very painful. However, this form is much rarer. If you experience these symptoms, please contact your GP or pharmacist immediately.

The symptoms include:

  • Eye pain
  • Sudden loss of sight
  • Severe headaches
  • Blurred vision or halos around lights
  • Nausea/vomiting
  • Hazy, cloudy cornea upon examination

Treatments for Glaucoma

The main aims of glaucoma treatment are to reduce symptoms and progression of the disease. The only method of treating the condition is by decreasing the intraocular pressure to protect the optic nerve, achieved by various procedures described below.

Eye drops

Eye drops allow the delivery of an active drug directly onto the eye and can enter the watery fluid of the eye (aqueous humour). Once they have crossed the cornea or conjunctiva of the eye, they can decrease the intraocular pressure and prevent further damage to the optic nerve. 

The different classes of drugs for glaucoma eye drops available are based on the active ingredient of the eye drops, prescribed according to the type of glaucoma you have and what is most suitable for you. 

These include beta-blockers, prostaglandin analogues, carbonic anhydrase inhibitors, and adrenergic agonists. All of these drugs aim toward the normal functioning of the optic nerve by reducing intraocular pressure.4 Cholinergic agonists, although commonly used in the past, are no longer prescribed due to their extensive side effects.11 However, doctors may use cholinergic agonists on a patient before a surgical procedure to cause miosis of the eye (pupil constriction).

Some eye drops work by relaxing specific muscles in the eye called uveoscleral muscles. This class of drug is called prostaglandin analogues. Others work by decreasing the production of the aqueous humour and increasing trabecular and uveoscleral outflow to prevent pressure build-ups in the eye. These classes of drugs can be beta-blockers, carbonic anhydrase inhibitors, and alpha-adrenergic agonists. 

Glaucoma medications, like most medications, are only effective if you take them correctly. Ensuring daily administration as directed by your GP or pharmacist for this chronic condition is essential. Try taking your medication at the same time as daily activities, such as brushing your teeth, so you do not forget.

Laser Treatment and Surgery

These treatment methods are only recommended when the response to eyedrops and oral medications is not effective. It is only effective for specific types of glaucoma.3

Laser treatment for glaucoma is called trabeculoplasty and can only treat open-angle glaucoma. There are other laser treatments for different glaucoma types, some developed by the National Eye Institute.9 Laser treatment works in a few ways depending on the type used. A laser trabeculoplasty is used to open drainage channels in your eye to reduce the intraocular pressure by allowing more fluid drainage through the trabecular meshwork.12

There is also a cyclodiode laser treatment that uses a laser to destroy specific eye tissue that secretes aqueous humour, therefore decreasing intraocular pressure. Another option is laser iridotomy, where a laser is used to produce holes in the iris so more aqueous humour can drain from the eye.13

Most people will keep taking glaucoma medication after the laser treatment to prevent intraocular pressure from building up again. Several check-ups are necessary after the procedure, and as the treatment wears off over time, multiple laser treatments will be needed to prevent the intraocular pressure from increasing again or instead, glaucoma surgery.9

In the rare case that you do require surgery, there are a few options that you and your doctor can consider:

  • Glaucoma implant surgery - a tube is implanted into the white part of the eye to help drain fluid.9
  • Trabeculectomy - a small incision in the top of your eye that allows extra fluid to drain and intraocular pressure to decrease; it is used to treat open-angle glaucoma.

A newer surgery called minimally invasive glaucoma surgery, which uses microscopic-sized equipment to create tiny incisions, is a much less invasive surgery, so it is safer with fewer risks and post-surgery complications imposed.10

Neuroprotection, Neurodegeneration

Glaucoma can be classed as a neurodegenerative disease as it destroys neurons. In order to combat the development of glaucoma, neuroprotection is a strategy involving the prevention or delay of glaucomatous neurodegeneration. These strategies can actually halt the progress of glaucoma itself.8 

The main method of neuroprotection for glaucoma involves:

  • The reduction of intraocular pressure through eye drop medication can be considered a preventative method of optic nerve damage as this therapy reduces oxidative stress and neuroinflammation. These drugs are the classes of eyedrops previously described.

Future neuroprotective therapies in development:8

  • Antioxidants - As glaucoma increases oxidative stress through reactive oxygen species, introducing antioxidants could help treat the disease by reducing oxidative stress.
  • Stem cell therapy - Future treatments could focus on regeneration of the lost tissue; however, this is still a relatively new field of research with some ethical complications.

When to seek medical advice

As glaucoma is difficult to identify and diagnose early, your best chance of an early diagnosis is attending regular eye appointments where your ophthalmologist (eye doctor) can check your eye pressure.

You should seek medical advice immediately if:1, 5, 3

  • You experience sudden changes in your vision (peripheral loss, hazy vision, rainbows around lights)
  • Your eyes become red and painful
  • The appearance of your eye and pupil changes


Glaucoma is a serious condition and can cause irreversible blindness if ignored or left untreated. To prevent eye damage, remember to:

  • Be aware of your risk factors
  • Attend regular eye check-ups (every 6-12 months unless otherwise advised)
  • If you notice any sudden changes or vision loss, consult your GP immediately
  • Consider neuroprotective measures with your GP if you are at considerable risk of glaucoma
  • Be aware of your treatment options


  1. Glaucoma. [online]; NHS. 2021 [accessed 8 Mar 2022]. Available from:
  2. Natarajan JV, Ang M, Darwitan A, Chattopadhyay S, Wong TT, Venkatraman SS. Nanomedicine for glaucoma: Liposomes provide sustained release of latanoprost in the eye. International Journal of Nanomedicine. 2012;7: 123-131.
  3. Weinreb RN, Aung T, Medeiros FA. The pathophysiology and treatment of Glaucoma. JAMA. 2015;311(18): 1901-1911.
  4. Farkouh A, Frigo P, Czeika. Systemic Side effects of eye drops: a pharmacokinetic perspective. Clinical Ophthalmology. 2016;10; 2433-2441.
  5. Types of Glaucoma. [online]; Glaucoma Research Foundation. 2020 [accessed 8 Mar 2022]. Available from:
  6. What is Open-Angle Glaucoma? [online]; WebMD. 2021 [accessed 8 Mar 2022]. Available from:
  7. Khazaeni B, Khazaeni L. Acute Closed Angle Glaucoma. Statpearls [Internet]; 2022
  8. Gauthier AC, Liu J. Neurodegeneration and neuroprotection in Glaucoma. Yale J Biol Med. 2016;89(1): 73-79.
  9. Laser Treatment for Glaucoma. [online]; National Eye Institute. 2021 [accessed 8 Mar 2022]. Available from:
  10. What is MIGS? [online]; Glaucoma Research Foundation 2021 [accessed 9 Mar 2022]. Available from:
  11. Glaucoma Medications and their Side Effects [online]. Glaucoma Research Foundation 2018 [accessed 9 Mar 2022]. Available from:[12] Glaucoma Treatment [online]; NHS 2021 [accessed 11 Mar 2022]. Available from:
  12. Meyer JJ, Lawrence SD. What’s new in laser treatment? Current Opinion in Ophthalmology, 2012;23(2): 111-117. 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Laura Preece

BSc Pharmaceutical Sciences and MRes Pharmacy and Pharmaceutical Sciences
I am a researcher and medical writer with a passion for pharmaceutics, disease and biological sciences. I am currently researching cellular and molecular biology, investigating the use of vitamin C as an adjunctive therapy for diabetes mellitus.

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