The white part of your eye and the inner surfaces of your eyelids are covered by a transparent membrane (thin layer of cells) known as the conjunctiva. If the conjunctiva becomes inflamed, you have a condition called conjunctivitis.
There are three types of conjunctivitis: irritant, infective and allergic. Each type of conjunctivitis is caused by different factors.
Irritant conjunctivitis. Irritant conjunctivitis occurs when an irritant such as chlorine or an eyelash gets into your eyes. This can make your eyes sore, and if you rub them it can make the soreness even worse. Avoiding the irritant and not rubbing your eyes will help.
Infective conjunctivitis. Infective conjunctivitis can be caused by a virus, bacteria or, in rare cases, by a sexually transmitted infection such as Chlamydia or gonorrhea. The most common symptoms include reddening and watering of the eyes. You may also notice a sticky coating on your eyelashes, particularly when you first wake in the morning, which can make your eyes feel like they're stuck together. Infective conjunctivitis is a very common condition and is responsible for 35% of all eye-related problems recorded. It is most common in children and the elderly. It rarely requires any treatment because the infection will normally heal by itself, usually within one or two weeks. For some people a general antibiotic will be prescribed for bacterial infections.
Allergic conjunctivitis. Allergic conjunctivitis is a common condition and is responsible for 15% of all eye-related problems recorded. It occurs when your eye comes into contact with an 'allergen'. An allergen is a substance that makes your body's immune system react abnormally, causing irritation and inflammation in the eye. This is known as an allergic reaction. Common examples of allergens include pollen, dust mites and animal fur. There are a number of types of allergic conjunctivitis. The two most common types are outlined below.
Seasonal allergic conjunctivitis (Hay fever) is the most common type of conjunctivitis cases. Symptoms recur at the same time each year and are most commonly triggered by pollen.
2. Perennial allergic conjunctivitis symptoms occur all year round and are usually present when you wake in the morning. The symptoms can be caused by a variety of allergens, such dust mites or animal fur.