What is microbial keratitis?
This is a serious condition in which the cornea (the clear protective layer at the front of the eye) becomes infected. The usual cause is contact lens wear, but infection of the cornea can also happen when there is abnormal exposure of the eye, for example if the eyelids are not blinking normally, loss of sensation in the eye surface, following injury or surgery, insufficient tears (dry eye), and in people whose immune system is not functioning properly. The infection is usually caused by bacteria, although some cases are caused by fungi.
Microbial keratitis is a very serious condition. It usually begins suddenly with redness and pain in one eye. The eye waters and there may be a discharge. Light may hurt the eye, making it difficult to open. The vision of the eye may be blurred.
The optometrist will usually see a cloudy area on the normally clear cornea where the infection is present. There may also be an open sore (ulcer) on the surface of the cornea. Inflammation may also spread to the front part of the eye.
How is microbial keratitis managed?
Microbial keratitis is a sight-threatening emergency. In the case of small ulcers with a low risk of sight-threatening complications the optometrist may begin treatment with antibiotic eye drops. More serious cases will need to be referred on the same day to an ophthalmologist (specialist eye doctor). Contact lens wearers should be advised not to discard their lenses or lens cases as these may be needed to help identify the cause of the infection.
The ophthalmologist may take a small sample from the ulcer to find out what is causing the infection and will begin treatment with antibiotic eye drops. These will need to be put into the eye very frequently. The patient may need to stay in hospital so that treatment can continue day and night. If the infection is caused by a fungus, the treatment will usually be with anti-fungal eye drops and in some cases with tablets.
When the infection is controlled, steroid eye drops may be prescribed. If the infection was contact lens related, the patient will be given advice on whether it is safe to wear lenses again.
