Lowering intraocular (internal eye) pressure (IOP), is an important step in treating glaucoma. IOP rises when there’s more fluid entering the eye than leaving. Eye drops are usually the first line of defense to help to restore this balance and prevent further optic nerve damage and vision loss. Here are six (6) commonly prescribed categories of glaucoma eye drops, including how they work and what their side effects might be.*

About glaucoma eye drops

Glaucoma can eye drops lower IOP in two ways:

• Suppressing eye fluid production, and/or
• Increasing eye fluid drainage. 

Harvard Medical ophthalmology instructor Courtney Ondeck, M.D. notes that people can respond to eye drops in different ways, and not all eye drops are effective for everyone. Further, advanced glaucoma may require multiple drops to lower IOP. 

Side effects of eye drops can also vary from person to person, but some common ones include:

• Redness
• Stinging
• Itching
• Eye pain
• Dryness
• Blurred vision

Here are some of the specific ways that eye drops can differ.

Six (6) commonly prescribed categories of glaucoma eye drops

There are six (6) general categories of glaucoma eye drop medications commonly prescribed.

Prostaglandin analogs (PGAs)

PGAs, such as Xalatan® (latanoprost), Travatan Z® (travoprost), and Lumigan® (bimatoprost), increase fluid drainage from the eye to lower IOP. PGAs are taken once daily, and are generally well-tolerated. Side effects may include: 

• Change in eye color
• Droopy and darkened eyelids
• Eyelash growth

Beta-blockers

Beta-blockers, such as Betoptic® (betaxolol) and Timoptic® or Betimol® (timolol), decrease eye fluid production to lower IOP. Beta-blockers can have systemic (whole-body) side effects, such as:

• Low blood pressure
• Irregular heartbeat
• Breathlessness and/or fatigue

Carbonic anhydrase inhibitors (CAIs)

CAIs, including Neptazane® (methazolamide), Diamox® Sequels (acetazolamide), and Trusopt® (dorzolamide), decrease eye fluid production to lower IOP. Common side effects may include:

• Rash
• Taste alteration
• Stomach pain and/or nausea
• Mental fog and/or fatigue

CAIs must be taken several times daily, says Ondeck, and doctors should be cautious when prescribing CAIs for people with kidney issues.

Alpha agonists

Alpha agonists, such as Alphagan® P (brimonidine tartrate) and Iopidine® (apraclonidine), lower IOP by both decreasing eye fluid production and increasing drainage. They are typically taken three times daily. Potential side effects include:

• Headaches
• Eye dilation
• Elevated blood pressure
• Irregular heartbeat

Ondeck says older people may also experience significant fatigue and conjunctivitis (pink eye).

Rho kinase (ROCK) inhibitors

Rho kinase inhibitors, such as Rhopressa® (netarsudil), lower IOP by increasing fluid drainage.

Potential side effects include:

• Corneal deposits
• Stinging
• Minor eye bleeding

Rho kinase inhibitors are typically taken once per day for glaucoma.

Combination drops

Combination eye drops, such as Rocklatan® and Combigan®, contain two different medication categories for stubbornly high IOP. Combination drops are convenient for patients, says Ondeck, but the drops are sometimes only available in brand names, and insurance carriers don’t always approve them.

(Note: Cholinergic eye drops, such as Isopto® Carbachol or Miostat®, are another category of glaucoma medication, but are not commonly prescribed due to potential side effects.)

Be consistent

Once you’ve made a decision with your healthcare provider about which eye drop is right for you, the National Eye Institute (NEI) explains that your doctor will likely want you to stick with it every day as long as it’s working. Glaucoma medicines generally aren’t problematic for most people but, if side effects are an issue, NEI advises speaking to your doctor about possibly altering the dose or switching to a different eye medication.

States NEI, “Some people with glaucoma stop using their eye drops after a while. They may forget, get out of the habit, or think the medicine isn’t helping. Remember, glaucoma eye drops won’t make you feel different or improve your vision. They prevent your vision from getting worse. If you don’t use them as prescribed, you could lose your vision.”

*Marturana Winderl, A. (2022, December 30). 7 Types of Glaucoma Eye Drops. Health. https://www.health.com/condition/glaucoma/glaucoma-eye-drops