Red Eyes: Common Causes and When to Worry
We have all experienced bloodshot eyes at some point — after a late night, a long day staring at screens, or during allergy season. But while most cases of eye redness are harmless and temporary, some can signal conditions that need medical attention. Here’s how to tell the difference.
Common Causes of Red Eyes
Digital Eye Strain
The most common cause in modern life. Staring at screens reduces your blink rate by up to 60%, leading to dryness and irritation. Follow the 20-20-20 rule: every 20 minutes, look at something 20 feet away for 20 seconds.
Allergies
Allergic conjunctivitis causes red, itchy, watery eyes. Pollen, dust mites, and pet dander are common triggers. Over-the-counter antihistamine eye drops usually provide quick relief.
Dry Eye Syndrome
Chronic dry eye affects millions of people, especially those over 50. The eyes don’t produce enough tears or the tear film evaporates too quickly, leading to persistent redness and discomfort. Artificial tears and omega-3 supplements can help.
Conditions That Need Medical Attention
Acute Glaucoma
Sudden severe eye pain, redness, halos around lights, and nausea can indicate acute angle-closure glaucoma — a medical emergency. Seek immediate care if you experience these symptoms together.
Uveitis
Inflammation of the middle layer of the eye, often associated with autoimmune conditions. Symptoms include deep eye pain, light sensitivity, and blurred vision alongside redness.
Subconjunctival Hemorrhage
A bright red patch on the white of the eye that looks alarming but is usually harmless. It occurs when a tiny blood vessel breaks, often from sneezing, coughing, or straining. It typically resolves on its own within 1-2 weeks.
When to See an Eye Doctor
- Redness lasting more than 3 days
- Pain (not just irritation) in or around the eye
- Changes in vision
- Sensitivity to light
- Discharge (especially yellow or green)
- Recent eye injury or surgery
Disclaimer: This article is for informational purposes only and doesn’t replace professional eye care. Originally adapted from Korean content.