Medicated eye drops to lower intraocular pressure (IOP), or internal eye pressure, have long been the firstline treatment for glaucoma. Ophthalmologists have a wide range of drops to choose from, and they do their best to prescribe drops, or combinations of drops, that best suit each patient’s eye health and lifestyle needs. Here is a basic guide to the most commonly prescribed glaucoma drops, including their usual dosages and possible side effects.*

The main types of medicated eye drops used to treat glaucoma include:

• Prostaglandin analogues
• Beta-blockers
• Alpha adrenergic agonists
• Carbonic anhydrase inhibitors
• Miotics
• Fixed combinations

Prostaglandin analogues used for glaucoma are:

• Latanoprost
• Travoprost
• Bimatoprost
• Tafluprost

One drop is typically used once a day, only at night, though your doctor may prescribe daytime use in certain circumstances.

Side effects of prostaglandin analogues can include:

• Eye redness
• Darkening of the iris
• Discoloration of the skin, and loss of fat around the eye
• Darker, longer eyelash growth

Beta-blockers for glaucoma are:

• Timolol
• Betaxolol
• Levobunolol

One drop is usually administered twice a day, though time-release options are also available.

Using beta-blockers can:

• Exacerbate lung diseases
• Lower your blood pressure and heart rate
• Cause dizziness, insomnia, and impotence
• Alter your lipid (blood fat) profile

The alpha-adrenergic agonist Brimonidine is generally used either:

• Three times a day (if used by itself), or
• Twice a day (if used in combination with another eye drop)

Potential side effects of Brimonidine include:

• Itchy eyes
• Drowsiness
• Low blood pressure
• Breathing difficulties

Carbonic anhydrase inhibitors used to treat glaucoma are:

• Brinzolamide
• Dorzolamide

Carbonic anhydrase inhibitors are also typically used:

• Three times a day (if used alone), or
• Twice a day (if used in combination)

Side effects may include:

• Stinging sensation in your eyes
• Unpleasant taste in your mouth

In cases of very high IOP, your doctor may also prescribe the oral medication acetazolamide as a temporary supplement to your eye drops. Acetazolamide may cause:

• Tingling or numbness
• Altered sense of taste
• Indigestion, nausea, or vomiting,
• Skin rashes

The miotic pilocarpine has largely been replaced by new compounds, but is still sometimes used to treat angle-closure glaucoma or as a treatment prior to laser therapy.

Possible side effects of pilocarpine include:

• Eye pain
• Headache
• Contracted pupils
• Blurry vision, or reduced vision in dim lighting

Some of the medications discussed above can be combined in one bottle for your convenience, if your treatment requires two different prescriptions. Speak with your ophthalmologist about which options are best for you.

Sources: 

• World Glaucoma Association. (2023). What are the different eye drops used in the treatment of glaucoma?