When you are tired or lack of sleep, your eyes will turn red without any hurt or pain. For this reason, you need to have a rest and enough sleep. The most common cause red bloodshot eyes in people who don't where contact lenses are eye allergies, known as allergic conjunctivitis. Although the eyes often itch, they may not. There is sometimes accompanying nasal allergies, characterized by sneezing or nasal congestion. The causes of eye allergies are numerous, but common ones include mold, mites, and pollen. Your doctor will be able to prescribe eye drops or other allergy medications for you if this turns out to be the diagnosis. Mechanical irritation of the eyes from small particles in the air (dirt, dust, smoke) is also common in some occupations and also in runners and others who spend a lot of time outside. This usually responds to wearing protective eyewear and using rewetting drops or artificial tears.
