Keratitis

The front of your eye has a clear part.

This part can get sore and red. It may feel gritty like sand is in your eye. Light might also hurt your eyes.

Tiny germs can cause this soreness. Some germs come from wearing contact lenses. Other germs can come from tap water.

Doctors can test your eye to find the germ. They use special medicine to help you feel better. Keeping your lenses clean is very important.

Taking good care of your eyes helps them stay healthy.

Your eye has a clear dome on the front. This part is called the cornea. Keratitis is when the cornea becomes inflamed. This means it gets red and sore. You might feel pain or a gritty feeling. Light might also hurt your eyes.

Many things can cause this. Tiny germs like bacteria or viruses can cause it. Some people get it from wearing contact lenses. For these people, bacteria cause 90% of cases. One type of bacteria is called Pseudomonas aeruginosa. This germ makes enzymes that can digest the cornea.

Other germs can cause it too. Viruses like herpes simplex can cause it. This often makes a branching pattern in the eye. We call this a dendritic pattern.

Tiny living things called amoebas can also cause it. These are often found in tap water. It is very important to keep contact lenses clean. Do not store them in tap water. Using good care helps keep your eyes healthy.

Your eyes have a clear dome on the front surface. This part is called the cornea. Keratitis is a condition where this cornea becomes inflamed. It can be a very painful experience for a person. You might feel a gritty sensation in your eye. Your vision might become blurry or impaired. Many people also feel light sensitivity, which is called photophobia.

Different tiny germs can cause this inflammation. Viruses like herpes simplex can cause a branching pattern. Doctors call this a dendritic pattern because it looks like tree branches.

Bacteria are also a common cause. For people who wear contact lenses, bacteria cause 90% of cases. One germ is called Pseudomonas aeruginosa. This bacterium produces enzymes that can actually digest the cornea.

Other types of tiny living things can cause trouble too. Fungi like Aspergillus fumigatus can lead to fungal keratitis. Tiny amoebas called Acanthamoeba can also cause serious infections. These amoebas are often found in tap water. This is why you should never store contact lenses in tap water. There are even parasites that cause river blindness. This happens after a blackfly bite from a Simulium fly.

Doctors use many tools to find the cause of the problem. They often perform an eye examination to see the signs. They might take small corneal scrapings to test for germs. This is called a microbiological culture. In 2007, the U.S. Center for Disease Control issued a health advisory. This was about a risk linked to a specific eye solution.

This shows how important it is to watch for new risks.

Treating keratitis depends on what germ is causing it. Doctors may use antibacterial solutions like levofloxacin. For viruses, they might use drugs like acyclovir. Contact lens wearers must stop wearing their lenses right away. They should also replace their old lenses and cases. Keeping lenses clean and using the right solution helps a lot. Good hygiene is the best way to protect your eyes.

Keratitis is a medical condition defined by inflammation of the cornea. The cornea is the clear, dome-shaped structure located on the front surface of the eye. When this area becomes inflamed, it can lead to significant discomfort and health risks. Common symptoms include moderate to intense pain and a gritty sensation in the eye. Patients may also experience impaired eyesight, redness, and photophobia, which is a sensitivity to light.

To diagnose keratitis, doctors typically rely on clinical signs observed during an eye examination. If a doctor suspects an infectious cause, they may perform corneal scrapings. These samples are then evaluated using a microbiological culture or other specialized testing. This process helps identify the specific pathogen, or germ, causing the infection. Identifying the exact cause is vital because the treatment depends entirely on the type of infection present.

Viral keratitis is one major category of the condition. The most common causes are the herpes simplex virus (HSV) and the varicella zoster virus (VZV). Herpes simplex keratitis occurs when latent HSV reactivates within the ophthalmic nerve. This nerve is the V1 branch of the trigeminal nerve. This infection often presents with a dendritic pattern, which means the inflammation looks like branching tree limbs in the corneal epithelium.

Another viral type involves the varicella zoster virus. Approximately 8% to 20% of shingles cases involve the eyes as herpes zoster ophthalmicus. This also involves the reactivation of the virus in the V1 branch of the trigeminal nerve. VZV keratitis often appears about one month after the onset of shingles symptoms. It can cause clouding of the cornea. In about 50% of cases, inflammatory infiltrates appear in the stromal layer, which is a deeper part of the cornea.

Bacterial keratitis is another significant type, often linked to injury or contact lens use. For people wearing contact lenses, bacteria are responsible for 90% of keratitis cases. Among those cases, a bacterium called Pseudomonas aeruginosa causes 40%. This specific pathogen is dangerous because it produces enzymes that can digest the cornea. Other common bacterial pathogens include Staphylococcus aureus and various streptococci. Poor hygiene, such as using tap water or failing to replace lens cases, can lead to a biofilm. A biofilm is a layer of bacteria that can colonize lenses and cases.

Other infectious agents include fungi and amoebas. Fungal keratitis can be caused by Aspergillus fumigatus or Candida albicans. Amoebic keratitis is a serious infection often caused by Acanthamoeba. This organism is commonly found in tap water, which poses a risk to contact lens wearers. In 2007, the U.S. Center for Disease Control issued a health advisory regarding an increased risk of Acanthamoeba keratitis linked to a specific eye solution.

There are also non-infectious forms of keratitis caused by environmental factors. Exposure keratitis, or exposure keratopathy, happens when the cornea becomes too dry because the eyelids do not close completely. Photokeratitis is caused by intense ultraviolet radiation, such as snow blindness or welder's arc eye. Additionally, contact lens acute red eye (CLARE) is a non-ulcerative, sterile form of keratitis. This is associated with Gram-negative bacteria colonizing the contact lenses.

Treatment for infectious keratitis must be urgent to prevent the condition from progressing. Doctors use antibacterial solutions like levofloxacin or moxifloxacin for bacterial infections. For viral infections like HSV, they may use topical ganciclovir or oral medications like acyclovir. It is important to avoid steroid eye drops for certain viral ulcers. Using steroids on a dendritic ulcer caused by HSV can cause the ulcer to become "amoeboid" or "geographic" in shape. This means it spreads into a large, map-like shape. While many cases are treated successfully, some infections can cause corneal scarring, perforation, or even loss of the eye.