Top 10 causes of red eye
Red, bloodshot eyes -- although usually painless -- are not exactly attractive. Redness occurs when blood vessels near the surface of the eye become enlarged and dilated. If you have red eye, it is important to find out why. Red eyes have several causes. Sometimes the cause of a red eye is of little concern, but it can also be a sign of a medical emergency. It is always best to seek the advice of a medical professional.
1. Allergic Conjunctivitis
Conjunctivitis, or pink eye, is an inflammation or infection of the clear, protective layer that coats the front part of the eye. Conjunctivitis can be caused by allergies, bacteria, viruses, or toxic substances.
Uveitis is an inflammation of the eye's uvea. It can cause redness, pain, blurry vision, floaters and light sensitivity. Uveitis should be treated quickly because other complications, such as uveitic glaucoma or retinal and choriodal scarring, may occur if it lingers.
3. Dry Eye
Human tears function to lubricate, nourish and protect the surface of the eye. When the tears are not of good quality or quantity, the surface of the eye becomes dry. Chronic dryness causes the surface of the eye to become inflamed and blood vessels to dilate as a result, causing increased redness.
Blepharitis is a chronic infection and inflammation of the eyelid and eyelashes. Blepharitis may be caused by poor eyelid hygiene. Other causes include oily eyelid glands, allergic reactions, bacterial infections, or lice on the eyelashes.
5. Acute Angle-Closure Glaucoma
Unlike most types of glaucoma, acute angle-closure glaucoma causes several recognizable signs, including painful redness that usually occurs in one eye. Acute angle-closure glaucoma is a serious medical emergency and must be treated immediately.
6. Subconjunctival Hemmorage
A subconjunctival hemmorage is caused by a blood vessel that bursts. When broken, these vessels bleed and spread out underneath the conjunctiva, the clear coating on the surface of the eye. It can be caused by hard sneezing, coughing, intense straining, vomiting, trauma, high blood pressure, diabetes and sometimes from certain blood disorder problems.
When an eye suffers and injury, the blood vessels enlarge and dilate to bring cells to heal and repair the injury. This will cause redness.
8. Corneal Ulcer or Infection
The cornea is the clear, dome-like structure that helps the eye achieve clear vision. The cornea has no blood vessels of its own. When the cornea becomes infected, however, surrounding blood vessels enlarge, bringing immune system cells to help fight the infection. This redness is very easy to see.
9. Contact Lens Wear
In some individuals, wearing contact lenses every day (or for extended periods of time) can cause the eyes to appear red. Some people develop contact lens-induced dry eyes, which makes it difficult to wear contact lenses comfortably. In others, merely having a foreign body, such as a contact lens, in the eye causes redness.
10. Frequent Use of Eye Drops
Constant use of one of the widely available "get the red out" eye drops can cause dilation of the eyes' blood vessels. After the effect of the eye drop wears off, the blood vessels sometimes dilate larger, causing the eyes to appear even more bloodshot.