What causes Eye Redness?
Eye redness happens when the vessels at the surface of the sclera and conjunctiva, the white portion of the eye and the clear membrane over it, become swollen. The vessels can swell due to many causes, including sun exposure, dust, eye dryness, cold, allergies and other particles in the eye.
Here are also some other causes, including infections and inflammation that can cause bloodshot eyes:²
- Conjunctivitis is the swelling or infection of the clear tissue that lines the eyelids and covers the conjunctiva, the surface of the eye. It can cause eye redness and irritation.
- Blepharitis, which is a condition in which swelling develops along the edge of the eyelid.
- Uveitis is the inflammation of the uvea, and it may be related to exposure to toxins or an autoimmune disorder, or sometimes infection.
- Corneal ulcers are sores on the cornea that mostly result from serious bacterial or viral infections.
- Corneal scratches due to injury by dust, sand or damaged contact lenses.
- Acute glaucoma is a sudden increase in eye pressure which can be extremely painful and can cause severe visual problems, including eye redness.
- A subconjunctival haemorrhage is a bright red spot that can appear after straining or coughing hard. It is not associated with pain or any vision issues and will go away within a week or two.