Putting the Size of the Observable Universe in Perspective. The age of the universe is about 13.75 billion years. The diameter of the observable universe is estimated at about 28 billion parsecs (93 billion light-years). As a reminder, a light-year is a unit of length equal to just under 10 trillion kilometres (or about 6 trillion miles).
Red eye is the result of changes in the blood vessels in your eye that make your eye look red or bloodshot; it may occur in one or both eyes. Red eye is usually caused by irritation, infection or trauma. Even everyday causes, such as coughing, sneezing, crying, and lack of sleep, can lead to redness in your eye. Red eye is often accompanied by other eye symptoms, including burning, itching, soreness, tearing and discharge.
Itchy eyes can be caused by various eye conditions too. Dry eyes are known to cause discomfort and irritation. Blepharitis, a non-contagious eye disorder caused by bacterial or skin conditions, also causes itchy eyes. With blepharitis, the eyelids become dry, scaly, and itchy.