Medicated eye drops are the first line of treatment for glaucoma. All glaucoma drops are designed to reduce the pressure inside your eye (intraocular pressure, or IOP) to slow deterioration of the optic nerve. They all reduce the amount of fluid produced by your eye and/or increase the drainage of fluid out of your eye.

All eye drops for glaucoma can cause side effects. The most frequently reported include redness, stinging sensation in your eye, and temporarily blurred vision. It’s important to know what symptoms you may experience when using eyes drops to treat glaucoma and which ones should be addressed quickly.* 

What eye drops are most commonly prescribed?

Your ophthalmologist may prescribe one or more of the following medicated eye drops to treat your glaucoma:

• Alpha agonists 
• Beta blockers
• Carbonic anhydrase inhibitors (CAIs)
• Miotics
• Prostaglandin analogs

Alpha agonists

Alpha agonists are a class of chemical agents often used to treat hypertension by lowering blood pressure. Lowering blood pressure can help reduce IOP. 

Additional side effects of alpha agonists may include:

• Eye itching, tearing, and/or swelling
• Larger (dilated) pupil
• Headaches 
• Dry mouth 
• Increased blood pressure
• Fast or irregular heartbeat
• Nervousness or anxiety
• Feeling tired, weak, or dizzy

Do not drive or operate machinery if you feel dizzy, weak, or tired.

Beta blockers 

Like alpha agonists, beta blockers are medications that reduce your blood pressure. They do this by blocking the effects of the hormone epinephrine (adrenaline). This causes your heart to beat more slowly and with less force. 

Some possible side effects of beta blockers include:

• Breathing problems (in people with asthma, emphysema, or COPD)
• Slow or irregular heartbeat
• Feeling tired and/or dizzy, especially during exercise
• Depression 
• Change in sex drive or sexual function
• Difficulty detecting symptoms of low blood sugar (in people with diabetes)

Carbonic anhydrase inhibitors 

CAIs can be used to treat both open-angle glaucoma (OAG) and acute angle-closure glaucoma. They may be administered as an eye drop or taken orally as a pill.

Possible additional side effects of carbonic anhydrase inhibitors include:

• Skin rash (particularly in people allergic to sulfa drugs)
• Changes in sense of taste (especially regarding carbonated drinks)
• Upset stomach or nausea
• Tiredness or low energy
• More frequent urination (when taken orally)
• Tingling sensation around the mouth and fingertips (when taken orally)

Miotics 

Miotics work by contracting the ciliary muscle, which controls the movements of the lens and pupil. Some additional side effects of miotics can include:

• Nearsightedness  
• Reduced vision in low light or difficulty seeing in the dark
• Headaches (especially around your brow ridge)
• Retinal detachment

Retinal detachment is when the light-sensitive tissue that lines the back of your eye pulls away, causing either “floaters” (dark spots) or flashing lights to appear in your vision. If either of these symptoms occurs, contact your ophthalmologist right away.

Prostaglandin analogs

Prostaglandin analogs have the benefit of once-daily dosing, but their effectiveness varies from patient to patient, and sometimes additional medications are necessary. 

Possible side effects of prostaglandin analogs include:

• Irritation, as though something is in your eye
• Permanent change in your iris color 
• Increased thickness and length of eyelashes
• Skin darkening on your eyelid
• Upper respiratory infections
• Achy joints
• Sensitivity to light
• Gradual sinking of your eyes into their sockets

Certain symptoms, such as blurred vision, stinging, and redness, tend to improve with time. If any side effects persist or interfere with your daily activities, contact your ophthalmologist. They may be able to lower your dosage or change your medicine. 

Most side effects disappear when the medication is stopped. It’s vital to use your eye drops exactly as prescribed, every day. You should never stop using the medicated drops unless instructed to do so by your doctor.

*American Academy of Ophthalmology. (2019, Dec. 10). Glaucoma Eye Drops.