Corneal Infections

Urgent assessment is important

Seek urgent eye care for a painful red eye, reduced vision, light sensitivity or a red painful eye associated with contact lens wear. Corneal infections can progress quickly.

A corneal infection, also called infectious or microbial keratitis, occurs when microorganisms infect the clear surface at the front of the eye. The infection may be bacterial, viral, fungal or caused by organisms such as Acanthamoeba. Some infections remain superficial, while others can form a corneal ulcer and damage deeper tissue.

Symptoms of a corneal infection

• Eye pain or increasing discomfort
• Redness
• Blurred or reduced vision
• Light sensitivity
• Watering or discharge
• Foreign-body or gritty sensation
• A white spot or cloudy area on the cornea in some cases

Who is at risk?

• Contact lens wear, especially overnight wear
• Poor contact lens cleaning or storage
• Exposing contact lenses to tap water, swimming pools or spa water
• Eye injury, particularly with plant or soil material
• Previous corneal disease or surgery
• Severe dry eye or poor eyelid closure
• Reduced immune function or certain medications

Different types of corneal infection

Bacterial keratitis

Bacterial infections can develop quickly and are commonly associated with contact lens wear or a break in the corneal surface. They often require intensive antibiotic eye drops.

Viral keratitis

Herpes simplex and herpes zoster viruses can affect the cornea. Treatment may involve antiviral medication and requires specialist guidance because steroid eye drops are appropriate in some situations but can worsen others if used incorrectly.

Fungal keratitis

Fungal infections are less common but can occur after eye injury involving plant material or in eyes with other risk factors. Treatment often requires prolonged antifungal therapy.

Acanthamoeba keratitis

Acanthamoeba is a rare but serious infection strongly associated with contact lens wear and water exposure. It can be difficult to treat and requires specialist management.

How are corneal infections diagnosed?

Your ophthalmologist will examine the cornea closely and may take a small scraping or sample for microscopy and culture. The appearance of the cornea, the history of contact lens use or injury, and laboratory results help guide treatment.

Treatment and follow-up

Treatment is chosen according to the likely cause and may include antibiotic, antiviral, antifungal or anti-Acanthamoeba medication. Drops may be required very frequently at first. Follow-up is important because treatment may need to change as the eye responds or laboratory results become available.

Reducing your risk if you wear contact lenses

• Wash and dry your hands before handling lenses
• Follow the replacement schedule for your lenses
• Do not sleep in lenses unless specifically prescribed for overnight wear
• Avoid tap water, swimming or showering while wearing contact lenses unless appropriate protective measures are used
• Clean and replace your lens case as advised
• Stop lens wear and seek assessment if the eye becomes painful, red or light-sensitive