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.
So how hot does it really need to be in order to do this, and what type of lighter would you have to use? The average melting point of glass is somewhere around 1500 degrees Celsius. This is certainly hotter than most lighters get, and it would take quite a bit of time to heat the glass to this point. If you are looking to melt glass, however, you will find that you have to choose lighters that can offer a sustained flame that burns at a very high temperature.