How do eye drops treat glaucoma?
The purpose of the eye drops is to lower the pressure within the eye either by decreasing the amount of fluid (aqueous humour) that is produced or increasing its drainage from the eye. 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.
Here, you’ll find a breakdown of the primary eye drop types used for glaucoma treatment, to help you better understand exactly what it is you’ve been prescribed.
The medication used in this category of eye drops work by improving drainage of fluid from the eye to specifically to reduce high eye pressure (ocular hypertension).
Some primary examples of these include:
Latanoprostene Bunod (Vyzulta)
Some of these medications may cause certain changes to the eye, such as slight redness of the eye, changes to the iris colour, and darkening and/or lengthening of the eyelashes.1 These eye drops should be used once a day, usually at night.
Prostaglandins are generally considered to be effective in managing open-angle glaucoma (the most common form of glaucoma).2
This class of glaucoma eye drops works by reducing the production of fluid in the eye, and a commonly used medication that does this is Timolol (Timoptic).
Other examples of beta blockers include:
It is worth noting that beta blockers can cause some systemic (whole body) side effects such as slow pulse, asthma, dizziness, and fatigue.1 Your ophthalmologist can help you with some techniques to minimise these risks2.
These eye drops are generally used once or twice a day. They can also be prescribed in combination with other types of medication for best results.
Alpha agonists are a class of glaucoma eye drops that both decrease fluid production and increase fluid outflow. Examples of these include:
Generally, allergic reactions are the most common side effects of glaucoma eye drops. This can be due to a common type of preservative used in the production of certain eye drops.
However, the preservative used in Alphagan-P actually breaks down into natural tear components, and is, therefore, better tolerated by people who are allergic to glaucoma eye drops (either the preservative in the drug or the drug itself).2 This type of glaucoma eye drop usually needs to be put in the eyes 2-3 times a day.
Carbonic anhydrase inhibitors
This group of glaucoma eye drops works by reducing the amount of fluid that is produced in the eye. Examples include:
Carbonic anhydrase inhibitors are also available in pill form. Some people find that they have some problematic side effects when taking these, but your doctor will talk them through with you.
Carbonic anhydrase inhibitors are typically used 2-3 times a day, sometimes alone, but usually in combination with another anti-glaucoma eye drop.
Combination eye drops
Some people need more than one type of medication in order to control their intraocular pressure, which is where combination eye drops can help. They also reduce exposure to preservatives and potential allergic reactions.2 If you are prescribed a combination eye drop, your ophthalmologist will go into detail as to why and how they fit into your treatment plan.
Common combinations include:
Cosopt – a combination of timolol (beta blocker) and dorzolamide (carbonic anhydrase inhibitor). Cosopt PF is the preservative-free version. The drug is also available in generic form
Combigan – a combination of brimonidine (alpha agonist) and timolol (beta blocker)
Xalacom – a combination of latanoprost (prostaglandin) and timolol (beta blocker)
Simbrinza – a combination of brinzolamide (carbonic anhydrase inhibitor) and brimonidine (alpha agonist). This combination is free of beta blocker and may be suitable for people who cannot take beta blockers.
New glaucoma treatments
A new class of anti-glaucoma medication called Rho Kinase (ROCK) inhibitors has passed clinical trials in the UK, and this group of medications works by increasing the drainage of fluid from the eye.2
This new medication is the first of its kind in over 20 years and represents a huge leap forward in the science behind how certain drugs can manage glaucoma symptoms. To find out more, talk to your ophthalmologist.
Using eye drops for glaucoma treatment
Eye drops are the mainstay of glaucoma treatment and should be used exactly as directed. It’s really important to continue using the medications even if there are no obvious problems with your vision, as you could be putting your eyesight at risk by not following the recommended treatment.
Your ophthalmologist may need to try different preparations and combinations of drops to identify the balance that is most effective and/or doesn’t have as many side effects. Some eye drops might not be suitable for people with underlying medical conditions, so it’s important to give a complete health history to the doctor.
1. International Glaucoma Association. (no date). Types of glaucoma eye drops. [Online].
Available at: https://www.glaucoma-association.com/about-glaucoma/treatments/eye-drops/ [Accessed 22 May 2019].
2. Glaucoma.org. (no date). Medication guide. [Online].
Available at: https://www.glaucoma.org/treatment/medication-guide.php [Accessed 22 May 2019].