Keratitis Causes

There are a few possible causes of this eye condition, including infection, wearing your contact lenses for too long, or due to an eye injury. The treatment for keratitis will depend on what has caused it. The two main types of keratitis are noninfectious and infectious.¹ ²

Noninfectious keratitis is caused by some kind of physical damage to the eye. This could be due to:

  • wearing your contact lenses for too long,
  • swimming with your contacts in,
  • dust, objects or chemicals in the eye,
  • some kind of eye injury,
  • eye surgery,
  • sunburn of the eye (photokeratitis) or windburn,
  • allergies,
  • underlying immune problems.

Infectious keratitis (microbial keratitis) occurs when some kind of bacteria, virus, fungi or parasite gets into your eye, usually through some kind of damage to your cornea.

There are a number of causes of infectious keratitis: ³ ⁴

  • Bacterial: This often happens as a result of not using contact lenses properly. For example, they haven’t been cleaned properly, they have been put in with unwashed hands or worn too long.
  • Fungal: This is due to contact with some kind of fungi from the environment, for example while gardening, cycling or walking. Unclean contact lenses can also cause this.
  • Viral: This is usually an infection from a herpes simplex virus or shingles virus. Keratitis from herpes can also cause a dendritic ulcer on the cornea.              
  • Parasitical: If you wear unclean contact lenses or come into contact with infected water, parasites can get into your eye and cause an infection.

The type of Keratitis can also depend on the part of the cornea that is affected. For example, marginal keratitis is when the outer edge of the cornea is inflamed. Interstitial keratitis is an inflammation of the middle layers of the cornea.⁵

Some types of infectious keratitis can also be contagious. It’s even possible to transmit it to yourself. For example, if you have herpes, your eye can become infected if you touch it after touching somewhere on your body which is already affected.


Keratitis Diagnosis

Your optometrist will diagnose the cause of your symptoms and may be able to prescribe the best course of treatment. During your appointment, we will discuss your symptoms with you, as well as your general health. This will help with the diagnosis and to determine if there are other underlying health causes that could be affecting your eyes. We will also examine your eye to help determine the cause and the extent of the infection. We may use a slit lamp to look at the different parts of your eye in detail.

You may be referred to an ophthalmologist who may also request further tests to check for an infection. This can include taking a tear or corneal sample (biopsy).

Keratitis Treatment

The treatment of keratitis will depend on whether the condition is caused by inflammation or infection. For mild cases of non-infectious keratitis, artificial tears can help to soothe irritation. In more severe cases, anti-inflammatory eye medications may be necessary.

For infectious keratitis, your doctor may prescribe medicated eye drops, oral medications, or a combination of both. This can include antibiotics, antifungals, antivirals or biocides, depending on the cause of the infection. It’s important to keep an eye out for recurring infections, as sometimes it may be resistant to treatment or even worsen. If this is the case, you should make an appointment with your optometrist.


Keratitis Complications

If treated properly and in time, you should recover from keratitis. In severe cases, if it is not treated keratitis can cause permanent corneal scarring, corneal ulcers, increased eye pressure and even blindness.

Keratitis Prevention

Improper use and care of contact lenses is one of the highest risk factors for keratitis. You should always closely follow the advice of your optometrist. Wash your hands thoroughly before you touch your eyes, always use the correct cleaning solutions and replace your lenses regularly. You should also avoid swimming or sleeping in your contacts.

Try wearing glasses, sunglasses or other eye protection if you’re somewhere especially dusty. Also if you’re gardening or doing an activity where something could fly into your eyes, try to wear protection. If you do experience redness in your eye or any other keratitis symptoms, it’s important to make an appointment with your optometrist straight away. Do not try and treat the symptoms yourself, as sometimes over-the-counter eye drops can make an infection worse.⁶ Most mild cases of keratitis can be easily treated. If it’s not treated, or not treated early enough, complications can cause permanent damage to your eyesight. If you think you have keratitis, please contact the NHS. They can advise you about services in your area and give you a referral to an eye specialist if necessary.


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