Corneal Ulcer (Infectious Keratitis)

A corneal ulcer is an open sore on the cornea (the clear front surface of the eye) usually caused by infection. It's a serious condition that requires urgent treatment to prevent permanent vision loss. Contact lens wear is the most common risk factor in developed countries, but ulcers can occur from any cause of corneal injury or compromise.

What Is a Corneal Ulcer?

The cornea is the clear, dome-shaped window at the front of the eye. A corneal ulcer is:

• An area where the corneal surface has broken down
• Usually infected with bacteria, fungi, or other organisms
• Associated with inflammation
• Potentially vision-threatening, especially if near the center of the cornea

Difference from Corneal Abrasion

• Abrasion: superficial scratch, usually heals quickly
• Ulcer: deeper, involves infection, requires aggressive treatment

Causes and Risk Factors

Contact Lens Wear (Most Common)

Other Risk Factors

Ocular Conditions:

• Severe dry eye
• Previous eye surgery
• Blepharitis
• Corneal exposure (from incomplete lid closure)
• Previous corneal disease
• Herpes simplex eye infection

Trauma:

• Scratch or injury to the cornea
• Foreign body
• Chemical burns

Systemic Factors:

• Diabetes
• Immunosuppression
• Malnutrition
• Vitamin A deficiency (in developing countries)

Common Infectious Organisms

Bacteria (Most Common):

• Pseudomonas aeruginosa—especially in contact lens wearers (aggressive)
• Staphylococcus aureus
• Streptococcus species
• Moraxella

Fungi:

• Fusarium
• Aspergillus
• Candida
• More common after plant/organic matter injury

Other:

• Acanthamoeba—from water exposure (contact lens wearers)
• Herpes simplex virus
• Herpes zoster virus

Symptoms

Warning Signs

Symptom Progression

• Often starts as foreign body sensation
• Pain increases over hours
• Vision becomes increasingly blurry
• Light sensitivity worsens
• Discharge may develop

What You Might See

• Red eye (can be very red)
• White, gray, or yellowish spot on the colored part of the eye
• Cloudy cornea
• Pus in the eye (hypopyon—visible as a white layer in the lower part of the iris)
• Swollen lids

Diagnosis

Urgent Eye Examination

• Complete eye exam including visual acuity
• Slit lamp examination (microscope) to visualize the ulcer
• Assessment of ulcer size, depth, and location
• Check for hypopyon (pus in the eye)
• Evaluation of surrounding cornea
• Measurement of intraocular pressure

Corneal Cultures

For significant ulcers:

• Scraping of the ulcer for cultures
• Identifies the causative organism
• Guides antibiotic selection
• Especially important for severe, central, or atypical ulcers

Imaging

• Corneal topography (usually after healing)
• OCT of cornea (in some cases)
• B-scan ultrasound if view is obscured (to check for endophthalmitis)

Treatment

Emergency Treatment

Fortified Antibiotic Drops:

• Usually started empirically (before culture results)
• Fluoroquinolone (moxifloxacin, gatifloxacin) for mild to moderate
• Fortified antibiotics (specially compounded) for severe ulcers
• Initial dosing may be every hour around the clock

Treatment Depends on Severity:

Severity	Characteristics	Treatment
Mild	Small, peripheral, no infiltrate	Fluoroquinolone drops frequently
Moderate	Larger, approaching center	Fortified drops, hourly
Severe	Central, deep, hypopyon	Fortified drops, possibly hospital admission

Additional Treatments

• Cycloplegic drops—reduce pain from ciliary spasm
• Pain management—oral pain medication
• Avoid patching—allows monitoring and medication delivery
• Discontinue contact lens wear—dispose of current lenses and case

Treatment for Specific Organisms

Fungal Ulcers:

• Antifungal drops (natamycin, voriconazole, amphotericin B)
• Much longer treatment course (weeks to months)
• May need oral antifungals
• Often require surgical intervention

Acanthamoeba:

• Extremely difficult to treat
• Combination of multiple drops (PHMB, chlorhexidine, propamidine)
• Treatment for months
• Often requires corneal transplant

Herpes:

• Antiviral drops (trifluridine) or oral antivirals
• May need topical steroids (carefully, under supervision)

Follow-Up

• Very frequent follow-up initially (daily or every other day)
• Treatment adjusted based on response
• Cultures reviewed when available
• Gradual taper as healing occurs

Complications

Potential Outcomes

With Prompt Treatment:

• Most bacterial ulcers heal
• Scarring depends on size and location
• Central scars affect vision more than peripheral

Possible Complications:

• Corneal scarring (permanent)
• Vision loss
• Corneal perforation
• Endophthalmitis (infection inside the eye)
• Need for corneal transplant
• Loss of eye (rare, severe cases)

Factors That Worsen Prognosis

• Delayed treatment
• Large or deep ulcer
• Central location
• Virulent organism (Pseudomonas)
• Fungal or Acanthamoeba infection
• Immunocompromised patient

After Healing

What to Expect

• Corneal scarring may occur (depends on ulcer severity/location)
• Vision may be affected by scarring
• May need glasses or contact lenses for irregular astigmatism
• May eventually need corneal transplant if scarring is significant

Returning to Contact Lenses

Prevention

For Contact Lens Wearers

Essential Practices:

• Never sleep in contact lenses (unless medically necessary)
• Never swim or shower in lenses
• Never use tap water with lenses
• Replace lenses on schedule
• Use proper disinfection (not saline alone)
• Replace lens case every 1-3 months
• Wash hands before handling lenses
• Don't "top off" old solution

Warning Signs to Remove Lenses:

• Any redness
• Pain
• Light sensitivity
• Blurred vision
• Discharge

General Prevention

• Treat underlying conditions (dry eye, blepharitis)
• Protect eyes from injury
• Seek prompt care for any eye injury or infection
• Don't ignore persistent symptoms

Frequently Asked Questions

How serious is a corneal ulcer?

Very serious. Corneal ulcers can cause permanent vision loss within days if not treated promptly and aggressively. They are a medical emergency.

Can I treat this at home?

No. Corneal ulcers require prescription medications, often specialty medications, and close monitoring. Delays in treatment significantly worsen outcomes.

Will I go blind?

With prompt treatment, most corneal ulcers heal successfully. However, vision may be affected if scarring occurs, especially if the ulcer was central. Severe or delayed cases can cause significant permanent vision loss.

Can I wear contacts again?

Possibly, after complete healing and with strict precautions. Daily disposable lenses and excellent hygiene are essential. Some patients are advised not to return to contact lens wear. Your doctor will guide this decision.

How did I get this?

The most common cause in developed countries is contact lens wear, especially sleeping in lenses or poor hygiene. Other causes include eye injury, severe dry eye, and other corneal diseases.

How long does treatment take?

Treatment duration varies from a week to months depending on the organism and severity. Bacterial ulcers typically improve within days but require weeks of drops. Fungal and Acanthamoeba ulcers require prolonged treatment.

References