How do you get keratitis?

What is keratitis and where does it come from?

Keratitis is inflammation of the cornea, which is the clear dome-shaped tissue in front of the eye which covers the pupil and the iris. Keratitis can be caused by many things including infections with bacteria, viruses, fungi or parasites. Even a noninfectious keratitis can occur after a minor injury such as wearing contact lenses too long or a non-infectious disease.
The symptoms of keratitis are:

• eye redness
• pain
• discomfort
• irritation
• blurred vision
• photophobia

Not all of these symptoms are always present in every case of keratitis. If left untreated however, any keratitis, particularly if it is an infection, can become more serious and permanently damage the vision.
The individual viral causes of keratitis include common viruses such as the herpes virus (herpes simplex or herpes zoster) and also the chlamydia virus.
Contaminated contact lenses often have bacteria, fungi or parasites which can cause keratitis and a particular one we are always concerned about in contact lens wearers is the Acanthamoeba parasite. This parasite can inhabit the surface of the contact lens or even the contact lens carrying case. If the cornea becomes infected with Acanthamoeba, you should have what is called an infectious keratitis which requires urgent treatment.
Contaminated water such as swimming pools can irritate the cornea and weaken the delicate surface corneal epithelium resulting in a chemical keratitis. This is usually short lived, and once you are out of the swimming pool and after a few hours, this will disappear. However, there are also bacteria, fungi and parasites often found in water more often in oceans, rivers, lakes and hot tubs where there is not chlorine or other chemicals, and if this enters your eyes when you are swimming or bathing, you can get a keratitis. If you have got a healthy cornea, to begin with, you are unlikely to get infected, but if you have already a breakdown of your corneal epithelium such as contact lens overwear, dry eye or a scratch, this could lead to a more severe keratitis.
The risk factors of keratitis include

• Previous exposure to viruses such as herpes simplex or herpes zoster
• Contact lens wear particularly soft contact lenses
• Reduced immunity
• Being in a warm, humid climate
• Eye injury
• The use of corticosteroid drops

Corticosteroid drops are contraindicated in the presence of a keratitis which may be caused by a virus unless it is being closely monitored by the ophthalmologist who is using them for a specific reason of there being a disciform or corneal infiltrate as well.
Potential complications of keratitis include chronic inflammation, recurrence if it is a viral infection of the cornea, an open sore on the cornea such as a corneal ulcer, corneal swelling or infiltrate and oedema, and even corneal scarring. Keratitis can cause a temporary or permanent reduction of the vision.
If you think you have eye related signs or symptoms that may be keratitis, you should see an eye specialist (ophthalmologist) for an urgent initial examination. The doctor is likely to ask you what is causing the symptoms, go to the possible cause, indicate what type of tests you are going to need and then provide you with a treatment plan.