Inflammation
Either chronic or recurrent inflammation of the white of your eye, and the inside of the eye, are important causes of a red eye. Most serious causes also blur the vision.
Growths on the eye
These growths can spread onto your cornea, commonly seen when a pterygia is present, or may only involve the white of the eye. Any growth that is very recent, increasing in size, or could affect your vision, should be assessed. The irritation common with otherwise innocuous growths can be easily treated using lubricant drops such as Polytears, Refresh or Systane.