A red eye occurs when the fine blood vessels in the conjunctiva become dilated or irritated. In most cases, the cause is harmless, such as irritation from dry air, dust, or overtiredness. Sometimes it is due to inflammation or a small burst blood vessel, which may look dramatic but often heals on its own.
Possible causes
Conjunctival irritation
Dry air, drafts, dust, or smoke irritate the conjunctiva and lead to redness, often with burning or a foreign body sensation.
Conjunctivitis
An inflammation caused by viruses, bacteria, or allergies makes the eye red, watery, and sometimes crusted.
Burst blood vessel
A small hemorrhage under the conjunctiva appears as a conspicuous red patch but is usually harmless and disappears on its own.
Dry eyes
A lack of tear fluid irritates the surface and makes the eye appear red and tired.
Typical steps at the doctor's office
- 1The ophthalmologist asks about the onset, accompanying symptoms such as pain, visual disturbances, or light sensitivity, as well as possible triggers such as contact lenses, dust, or cosmetics.
- 2With the slit lamp, she examines the conjunctiva, cornea, and anterior chamber of the eye; if necessary, she stains the cornea or measures the intraocular pressure.
- 3Depending on the cause, artificial tears and avoiding the trigger may be sufficient, or an inflammation is treated specifically.
What you can do yourself
- Avoid rubbing and allow the eye to rest.
- Remove contact lenses temporarily and wear glasses instead.
- Ensure fresh, not overly dry indoor air and avoid smoke.
- Cool, clean compresses can pleasantly soothe an irritated eye.
If the redness persists for more than a few days, keeps returning, or is accompanied by pain, changed vision or pronounced sensitivity to light, you should seek advice from an ophthalmologist. Earlier assessment is also advisable for contact lens wearers. This allows a simple irritation to be distinguished from a cause requiring treatment.
Frequently asked questions
- Is a red eye contagious?
- That depends on the cause. Irritation or a burst blood vessel are not contagious, but conjunctivitis caused by viruses or bacteria is. With crusted, watery eyes, caution with towels and hand hygiene is advisable.
- The red patch in my eye looks terrible – is it dangerous?
- A widespread red patch is usually a harmless small hemorrhage under the conjunctiva that disappears without treatment within one to two weeks. However, if pain or visual disturbances occur, you should still have it examined.
- Can screen work cause red eyes?
- Yes, prolonged work at a screen and dry indoor air irritate the eyes and make them appear red and tired. Breaks, conscious blinking, and fresh air help.
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