There are 17 conditions associated with discharge or mucus in eyes, drainage or pus and yellow eyes. The links below will provide you with more detailed information on these medical conditions from the WebMD Symptom Checker and help provide a better understanding of causes and treatment of these related conditions.
Burning glass. A burning glass or burning lens is a large convex lens that can concentrate the sun's rays onto a small area, heating up the area and thus resulting in ignition of the exposed surface. Burning mirrors achieve a similar effect by using reflecting surfaces to focus the light.
Glass is formed by heating sand to its melting point. Objects are then either cast or blown to their desired shape and allowed to cool slowly. Glass is made from a mixture of sand and other materials. Just regular sand can be made into glass, but it must be heated to about 3,000 degrees Fahrenheit.