Glaucoma is one of the top causes of permanent blindness worldwide. It refers to a group of eye conditions that gradually damage the optic nerve, often due to increased pressure inside the eye, called intraocular pressure (IOP). While this damage can’t be reversed, early treatment can slow or prevent further vision loss. Among available treatments, prostaglandin analogs (PGAs) are often recommended first because they are effective, easy to use, and generally well tolerated. Here we explore how PGAs work, how well they perform, and why some people respond better to them than others.

How PGAs Lower Eye Pressure

Prostaglandins are natural compounds in the body involved in many processes, including inflammation and fluid regulation. PGAs are man-made versions used as eye drops to treat glaucoma. They lower IOP by helping fluid drain more easily out of the eye, mainly through the uveoscleral pathway, one of the eye’s natural drainage routes.

These medications target specific receptors in the eye to relax tissues and reshape drainage channels. This allows excess fluid to exit more efficiently, reducing pressure on the optic nerve. The most common PGAs include:

• Latanoprost,  
• Bimatoprost, and 
• Travoprost. 

A newer drug, omidenepag isopropyl, works through a slightly different pathway and is also effective.

Comparing Effectiveness and Side Effects

Studies have shown that all major PGAs help lower IOP, but they differ slightly in how well they work and what side effects they may cause. 

• Long-term use of bimatoprost (0.03%) appears to be the most effective, followed by 
• latanoprost (0.005%) and 
• travoprost (0.004%). 

After just one month, all three perform similarly, but over time, bimatoprost tends to offer slightly more pressure reduction.

In terms of side effects, most are mild and occur in or around the eyes. These include redness (conjunctival hyperemia), eyelash growth, and mild irritation, like itching or dryness. Latanoprost tends to cause fewer side effects compared to the others, which may make it a better choice for some patients. PGAs are generally safe for the rest of the body, with few serious side effects reported.

Why Some People Respond Differently

Not everyone responds to PGAs the same way, and genetics may explain why. Researchers have found that certain gene variations—called single-nucleotide polymorphisms (SNPs)—can affect how well a patient responds to drugs like latanoprost. For example, changes in genes related to drug transport or prostaglandin receptors may improve or reduce the drug’s effectiveness.

This field of research, known as pharmacogenetics, aims to match patients with the treatments that will work best for them based on their genetic profile. While it’s still developing, it may soon help doctors make more personalized treatment decisions for glaucoma patients.

Takeaway

Prostaglandin analogs are a common first-line treatment for glaucoma, thanks to their strong performance and manageable side effects. Bimatoprost shows the greatest pressure-lowering effect, while latanoprost offers the best balance of effectiveness and comfort. As science advances, understanding how genetics affects treatment could lead to more precise and effective care for people living with glaucoma.

*Zhou, L., Zhan, W., and Wei, X. (2022, October 11). Clinical pharmacology and pharmacogenetics of prostaglandin analogues in glaucoma. Frontiers in Pharmacology.

Front Pharmacol. 2022 Oct 12;13:1015338. doi: 10.3389/fphar.2022.1015338

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