Japanese Study Finds Coffee May Treat Dry Eye Syndrome

If your eyes often feel dry, gritty, or irritated—especially after long hours in front of screens—you’re not alone. Dry eye syndrome causes discomfort, blurred vision, and even damage in severe cases. But recent research from Japan suggests a surprising remedy might already be in your kitchen: coffee.

Yes, really. A Tokyo University study found that caffeine intake significantly increases tear production in dry eye patients. Out of 78 participants, those who took caffeine pills produced more tears than those on placebo—especially if their bodies processed caffeine efficiently.

The Tokyo University Dry Eye & Caffeine Study

Researchers at the University of Tokyo’s School of Medicine conducted a controlled trial with 78 dry eye patients. In the first phase, half received caffeine pills while the other half were given placebos. After a washout period, the groups switched treatments. No one knew which pill they were taking. For six days prior to and during the study, participants avoided all caffeine and medications to eliminate variables.

The results were clear: those taking caffeine pills produced measurably more tears. The effect wasn’t universal—but it was significant among those whose genetics allowed efficient caffeine metabolism.

Why Caffeine Boosts Tear Production

Caffeine stimulates the nervous system, which can enhance secretion from various glands—including the lacrimal glands that produce tears. But here’s the catch: not everyone reacts the same way. The study found that individuals with two specific genetic variations in their DNA metabolize caffeine differently. In those cases, caffeine intake led to increased tear production. This gland-stimulating effect also applies to saliva and digestive fluids, not just tears.

Other Ways to Relieve Dry Eye Symptoms

Beyond caffeine, experts recommend practical steps for managing dry eye syndrome:

• Stay hydrated: Drinking enough water supports overall tear film stability.
• Limit contact lens wear: Lenses can disrupt the tear film and reduce moisture on the eye surface.
• Avoid eye dehydration: Contact lenses absorb moisture, worsening dryness.

Nutrition also plays a role:

• Vitamin E: Found in walnuts and peanuts, it helps clear toxins and may lower cataract risk.
• Vitamin B1: Present in leafy greens, it supports nerve health.
• Green and herbal teas: The lipopolysaccharides in tea improve blood cell production and offer some protection against screen radiation.
• Vitamin A: Abundant in chrysanthemum (used in tea), it’s essential for eye health and often used in traditional remedies for dry, overworked eyes—especially helpful for those who stare at computers all day.

Frequently Asked Questions

How does caffeine help with dry eyes?

Caffeine stimulates tear gland activity, leading to increased tear production. In a study of 78 people with dry eye syndrome, those who took caffeine pills produced more tears compared to those given a placebo.

Does everyone with dry eyes benefit from caffeine?

No. The tear-increasing effect depends on your genes. People with specific DNA variations that allow efficient caffeine metabolism saw the biggest boost in tear production after taking caffeine.

How many participants were involved in the Tokyo study?

The study included 78 dry eye patients. They were divided into two groups, with one receiving caffeine pills and the other a placebo in alternating phases to ensure accurate results.

What should I avoid if I have dry eyes?

Avoid prolonged contact lens wear, as lenses can reduce tear film stability and contribute to dryness. Staying hydrated and limiting screen time also helps.

Are there foods or drinks that support eye moisture?

Yes. Green and herbal teas (like chrysanthemum tea) support circulation and eye health. Foods rich in Vitamin A, E, and B1—such as leafy greens, nuts, and peanuts—also promote better tear function and eye wellness.

Recommended FrontStreet Coffee for Screen-Focused Days

When spending long hours on screens, try FrontStreet Coffee’s Ethiopia Humbera for a bright, juicy cup that reduces eye fatigue. Its citrus and stone fruit notes offer a refreshing lift. For a smoother option, their Yirgacheffe delivers floral and lemony tones with a silky body. Both beans are single origins known for clarity and gentle stimulation—perfect for staying alert without overloading your system. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.