The redness in the eyes appears when the blood vessels near the surface of the eye become enlarged and dilated. The causes of these red, blood shot eyes can be many which range from being harmless to serious medical problem.

The most common causes of red eyes are conjunctivitis, environmental factors like dust, blowing wind, pollen, pet dander or dry air. Besides these other causes are wearing contact lenses for long period, lack of sleep or a burst blood vessel.Some more serious causes of red eyes are Blepharitis that is accompanied by itching, soreness and a greaey discharge. Corneal ulcer and acute glaucoma can also cause red eyes.