There are 3 main types of conjunctivitis:
Viral conjunctivitis is the most common. It is caused by a virus as with the common cold. It is very contagious and just like a cold there is no cure (it does not respond to antibiotics). It can get worse in the first week and in severe cases, complications can occur. It is very important wash your hands each time you touch your eyes to try and prevent passing the condition onto your family and friends. Often, redness starts in one eye and then over the course of a few days the other eye also becomes red and watery.
Bacterial conjunctivitis is the 2nd most common. It is also contagious. There is usually a thick discharge. Although most cases are self-limiting, antibiotics will shorten the duration of the infection.
Allergic conjunctivitis is a response to something that you are allergic to. It is not contagious. The eyes are usually very itchy, red and watery. Sometimes, people become allergic to eye-drops that they are using. The eyes can become red and sore. You must see your Ophthalmologist to check whether it is safe to discontinue the eye-drops.
Not all red eyes are due to conjunctivitis. Other causes include corneal infections, acute glaucoma, iritis, episcleritis and scleritis.
A pinguecula is a raised yellowish patch or bump in the thin membrane (the conjunctiva) that covers the white of the eye (sclera). It is not a tumour, but an area of aged/degenerated collagen with deposition of protein, fat and/or calcium. Although mainly age-related, a pinguecula may also be a response to chronic eye irritation or sunlight.
No treatment is necessary unless it becomes inflamed. A pinguecula does not grow onto the cornea or threaten sight (unlike a pterygium). If particularly annoying, a pinguecula may on occasion be surgically removed.