Keratitis – Symptoms and Causes

Overview

Keratitis affects the cornea, the clear dome-shaped covering on the eye’s front. This inflammation can develop with or without an infection.

When no infection is present, keratitis might result from minor injuries like wearing contact lenses too long or getting something in your eye. Infectious forms of keratitis can stem from bacteria, viruses, fungi, or parasites.

If you notice red eyes or other keratitis symptoms, it’s important to see an eye doctor quickly. Most mild to moderate cases respond well to prompt treatment without vision loss.

However, untreated keratitis or severe infections can cause lasting vision damage.

Eye specialists can diagnose the condition through examination and may use tests to identify specific infectious causes. Early treatment typically involves addressing underlying causes and reducing inflammation to prevent complications.

Signs of Eye Infection

Keratitis may cause several noticeable symptoms:

• Redness in the eye
• Pain or discomfort
• Excess tears or discharge
• Trouble opening your eyelid
• Blurry or decreased vision
• Light sensitivity
• The feeling of something stuck in your eye

If you notice any of these symptoms, see an eye specialist right away. Quick treatment is important because delays can lead to serious problems, including possible blindness.

Causes

Keratitis occurs when the cornea becomes inflamed. Several factors can lead to this eye condition:

Physical damage to the cornea can cause non-infectious keratitis. When something scratches or injures the corneal surface, it may also create an opening for microorganisms to enter, potentially leading to infectious keratitis.

Contact lens issues are common triggers. Microorganisms can grow on lenses or lens cases and transfer to the eye during wear.

Poor lens cleaning habits or wearing contacts longer than recommended increases risk for both infectious and non-infectious forms.

Viral infections contribute to many cases, particularly:

• Herpes simplex virus
• Herpes zoster virus

Bacterial sources frequently include:

• Staphylococcus
• Streptococcus
• Pseudomonas

Water exposure can introduce harmful organisms. Swimming in oceans, lakes, rivers, or hot tubs may expose eyes to bacteria, fungi, and parasites.

However, healthy corneas typically resist infection unless the surface has already been compromised, such as from extended contact lens wear.

Risk Factors

Several factors can increase your chance of getting keratitis:

Contact Lens Use

Wearing contacts, particularly sleeping in them, raises your risk of both infectious and non-infectious keratitis. The danger often comes from:

• Wearing lenses longer than recommended
• Not cleaning them properly
• Swimming while wearing contacts

People who wear extended-wear contacts (continuously) face a higher risk than those who use daily wear lenses and remove them at night.

Weakened Immune System

If you have a weakened immune system due to illness or medications, you may be more likely to develop keratitis.

Corticosteroid Eye Drops

Using these drops to treat other eye conditions can increase your risk of infectious keratitis or worsen existing cases.

Previous Eye Injury

Damage to your cornea from a past injury can make you more vulnerable to keratitis.

Complications

Keratitis can lead to several serious problems if not treated properly. These include:

• Long-lasting inflammation and scarring of the cornea
• Recurring viral infections affecting the cornea
• Corneal ulcers (open sores on the eye surface)
• Vision loss that may be temporary or permanent
• Complete loss of sight in severe cases

Ways to Protect Your Eyes

Contact Lens Care Tips

Taking good care of your contact lenses helps prevent eye infections. Here are important steps to follow:

• Remove your daily wear contacts before sleeping
• Clean your hands thoroughly with soap and water before touching lenses
• Use only products made specifically for your type of contact lenses
• Follow all care instructions from your eye doctor
• Replace lenses according to the recommended schedule
• Get a new contact lens case every 3–6 months
• Use fresh solution each time you clean your lenses—never “top off” old solution
• Keep contacts away from water—don’t swim while wearing them

Proper cleaning and handling of contact lenses reduces your risk of developing serious eye problems. When in doubt about lens care, ask your eye doctor for guidance.

Stopping Virus Spread

While some viral eye infections can’t be completely prevented, you can take steps to reduce your risk:

Key prevention actions:

1. Avoid touching your eyes if you have cold sores or herpes blisters
2. Always wash hands thoroughly before touching your eyes or the area around them
3. Only use eye drops prescribed by an eye doctor
4. Wash hands frequently throughout the day

Viruses that cause eye infections can spread easily from your hands to your eyes. This is especially important if you or someone close to you has an active viral infection like a cold sore.

If you wear contact lenses and develop eye redness, pain, light sensitivity, or vision changes, remove your contacts immediately and contact your eye doctor.

Remember that good hygiene—especially hand washing—is your best defense against many types of eye infections.