# What Causes Bloodshot Eyes and How Do They Clear?

Source page: https://www.kudretgozistanbul.com/en/blog/eye-diseases/what-causes-bloodshot-eyes

**Author:** Kudret Eye İstanbul | **Medical Approval:** Op. Dr. Mehmet Ali Özdil | **Date:** 2026-09-10

> **Summary:** Bloodshot eyes (conjunctival hyperaemia) are redness of the white of the eye caused by widened small blood vessels, commonly from tiredness, lack of sleep, dry eye, allergy or infection, and often clear once the cause is removed. A subconjunctival haemorrhage, a sharply outlined red patch from a burst vessel, is a different condition and usually clears by itself within one to two weeks.

## Quick Facts
- **Medical name:** Conjunctival hyperaemia
- **Simple redness:** Clears within a few days to 2 weeks once the cause is removed
- **Subconjunctival haemorrhage:** Painless, does not affect vision, usually clears within one to two weeks without treatment
- **Hyphaema** (blood in the front chamber): Needs an ophthalmologist

---

## Causes of Bloodshot Eyes
- Focusing on one point for a long time
- Lack of sleep, fatigue, not resting the eyes
- Wearing contact lenses too long
- Dry eye
- Eye allergies
- Conjunctivitis
- Blepharitis (inflammation of the eyelid margins)
- Eye injuries
- Age-related eye conditions
- Rarely, a sudden rise in eye pressure (acute glaucoma); a stye can also cause redness

## Causes of Subconjunctival Haemorrhage
Forceful coughing, sneezing or vomiting, straining or lifting a heavy load, injury, blood thinning medication, high blood pressure, diabetes and clotting disorders.

## Bloodshot Eyes in Babies
Generally due to bacterial or viral infection or allergy; bacteria in the birth canal can pass to the baby during delivery. Treatment follows tests; persistent redness should be seen by a paediatric ophthalmologist.

## Symptoms
- Visible blood vessels on the white of the eye
- Swelling
- Itching and irritation
- Light sensitivity
- Eye pain
- Blurred vision
- A feeling of fullness
- Stinging

## Diagnosis
- Medical and family history and other eye conditions.
- Physical examination for injury or structural change, eye pressure measurement and examination of the inside of the eye for bleeding or trauma.
- Blood tests or ultrasound if a serious problem is suspected.

## Treatment
- Dry eye: artificial tears.
- Allergy: antiallergic drops.
- Bacterial infection: antibiotic drops, and pain-relieving drops if needed, only on a doctor's advice.
- Subconjunctival haemorrhage: usually no treatment; if it recurs often, check blood pressure and clotting.
- Serious injuries are assessed and treated separately by an ophthalmologist.

## When Are Bloodshot Eyes Dangerous?
When redness affects both eyes and does not clear, or comes with watering, itching, tenderness, stinging, pain, light sensitivity, swelling, blurred vision, sight loss or frequently recurring bleeding: see a doctor as soon as possible.

---

## Frequently Asked Questions

**Q: Do bloodshot eyes clear by themselves?**
A: With simple causes they can clear within a few days to 2 weeks; if they persist, consult a doctor.

**Q: Are bloodshot eyes normal in babies?**
A: They usually come from infection or allergy; if they persist, see a paediatric ophthalmologist.

**Q: Should I use eye drops?**
A: Not at random; the doctor decides which drop is appropriate.