Corneal Ulcer: Symptoms, Types, Causes and Treatment

Corneal ulcers are a significant cause of eye discomfort and vision loss worldwide. This article provides a comprehensive and evidence-based overview of corneal ulcers, focusing on their symptoms, types, causes, and current treatment options. If you've ever wondered why a "simple" red eye can sometimes become a vision-threatening emergency, understanding corneal ulcers is essential.

Symptoms of Corneal Ulcer

A corneal ulcer doesn't just manifest as a sore on the eye's surface—it can cause a range of symptoms that can escalate quickly. Recognizing these symptoms early can make a major difference in outcomes. Here’s what you should watch out for.

Symptom	Description	Severity	Source(s)
Pain	Sharp, aching, or severe	High	1 2 3
Redness	Especially around cornea	Moderate	1 2 3
Foreign body sensation	Feeling of something in the eye	Moderate	1 3
Photophobia	Sensitivity to light	High	1 3
Watering	Excessive tearing	Moderate	1 3
Discharge	Mucopurulent or watery	Variable	1
Blurred vision	Decreased visual acuity	Variable	1 2
Hypopyon	Pus in the anterior chamber	Severe	2 8

Table 1: Key Symptoms

Pain and Discomfort

Pain is often the most prominent symptom. Patients might describe it as sharp, stabbing, or throbbing. In some cases, the pain becomes so severe that it interferes with daily activities 1 2 3.

Redness and Inflammation

Redness, especially a ring of redness around the cornea (circum-corneal injection), is a classic sign. This is caused by inflammation in response to infection or injury 1 2.

Foreign Body Sensation and Photophobia

Many patients report a persistent feeling that something is in their eye (foreign body sensation), even when nothing is visible. Bright lights can worsen pain (photophobia), making it difficult to keep the eye open 1 3.

Watering, Discharge, and Blurred Vision

Tearing (lacrimation) and discharge are common, with the type of discharge (clear, mucous, or pus-like) varying depending on the cause. As the ulcer progresses, vision may become blurred, which can be a sign of deep involvement or complications 1 2.

Severe Signs: Hypopyon

In advanced cases, a visible layer of pus can collect in the lower part of the eye's anterior chamber (hypopyon). This is a sign of severe infection and inflammation, often requiring urgent intervention 2 8.

Types of Corneal Ulcer

Corneal ulcers are not all the same. They are classified based on their underlying cause and clinical characteristics. Understanding these types is key to effective management.

Type	Main Features	Common Causes	Source(s)
Infectious	Microbial involvement	Bacteria, fungi, viruses, parasites	3 5 12
Non-infectious	No active infection	Autoimmune, exposure, neurotrophic	6 7
Location-based	Central, marginal, peripheral	Varies	4 5
Special forms	Neurotrophic, marginal, dendritic	Nerve damage, lid disease, HSV	6 7 5

Table 2: Classification of Corneal Ulcers

Infectious Corneal Ulcers

These are the most common and result from infection by bacteria, fungi, viruses, or parasites. Each organism produces characteristic ulcer patterns:

• Bacterial: Rapid progression, often with pus and stromal infiltration. Pseudomonas (notably in contact lens users), Staphylococcus, and Streptococcus are frequent culprits 2 5 10.
• Fungal: Often follows plant or organic trauma, progresses more slowly, sometimes with feathery borders. Aspergillus, Fusarium, and Candida are the main agents 5 10 12.
• Viral: Herpes simplex virus (HSV) causes dendritic (branching) ulcers, common in both adults and children 5 9.
• Protozoal (Acanthamoeba): Associated with contact lens use, causing severe pain out of proportion to clinical appearance 5.

Non-infectious Corneal Ulcers

These ulcers occur without active infection. Main subtypes include:

• Neurotrophic ulcers: Result from loss of corneal sensation due to nerve damage (e.g., from herpes infection, diabetes, or surgery), leading to impaired healing 6 7 16.
• Autoimmune/Inflammatory: Conditions like rheumatoid arthritis or Sjögren syndrome can cause sterile (aseptic) ulceration 6 7.
• Exposure and Toxicity: Poor lid closure, toxic eye drops, or severe dry eye can lead to ulceration 6.

Other Classifications

• Location-based: Central (directly affecting vision), marginal (peripheral, may be linked to lid disease), or peripheral ulcers 4 5.
• Special forms:
  • Marginal catarrhal ulcers: Secondary to chronic eyelid disease (like staphylococcal blepharitis) 4.
  • Dendritic ulcers: Characteristic of HSV infection 5.

Causes of Corneal Ulcer

Corneal ulcers have diverse causes. Understanding them is crucial for prevention and tailored therapy.

Cause	Mechanism	Risk Factors	Source(s)
Infection	Microbial invasion of cornea	Trauma, contact lens, poor hygiene	1 2 5 10 12
Trauma	Direct injury, especially with organic material	Farming, manual labor	2 10
Contact lenses	Poor hygiene, overnight wear	Improper use	1 5
Systemic disease	Autoimmune or nutritional deficiency	Sjögren, vitamin A deficiency	6 7 9
Ocular surface disease	Dry eye, lid dysfunction	Aging, surgery	6 7 11

Table 3: Main Causes

Infectious Causes

• Bacterial: Most common worldwide. Streptococcus pneumoniae, Pseudomonas aeruginosa (especially in contact lens wearers), and Staphylococcus species are leading pathogens 2 4 5 10.
• Fungal: Especially prevalent in tropical regions and after trauma with plant material. Aspergillus and Fusarium dominate 10 12.
• Viral: HSV is a major cause, especially in children and immunocompromised individuals 5 9.
• Parasitic (Acanthamoeba): Associated with exposure to contaminated water and contact lens misuse 5.

Traumatic Causes

• Direct injury (e.g., from agricultural work, sticks, or other foreign bodies) compromises corneal integrity, allowing microbes to invade 2 10.
• Trauma is the leading predisposing factor in many developing regions 2 10.

Contact Lens Use

• Improper hygiene, extended wear, and overnight use of contact lenses significantly increase risk—especially for Pseudomonas and Acanthamoeba infections 1 5.
• Poor lens cleaning, use of contaminated solutions, and swimming with lenses further heighten risk 1.

Systemic and Ocular Surface Disease

• Autoimmune conditions: Rheumatoid arthritis and other diseases can cause sterile (non-infectious) corneal ulcers 6 7.
• Nutritional deficiency: Vitamin A deficiency, especially in children, predisposes to ulceration and blindness 9.
• Dry eye and eyelid disorders: Conditions like Sjögren syndrome, lagophthalmos (incomplete lid closure), or abnormal eyelashes can lead to persistent exposure and ulceration 6 7 11.

Other Contributing Factors

• Smoking, lower socioeconomic status, and poor access to healthcare further increase risk 1 2.
• In children, measles infection is a significant contributor to corneal ulceration and blindness in some regions 9.

Treatment of Corneal Ulcer

Timely and appropriate treatment is crucial to prevent vision loss. The approach depends on the cause, severity, and response to initial therapy.

Treatment	Purpose	Common Indications	Source(s)
Antimicrobials	Kill causative organisms	Infectious ulcers (bacterial, fungal, viral)	1 2 3 5 12 13
Supportive therapy	Promote healing, reduce pain	All ulcers	6 7 14
Surgery	Repair or replace tissue	Non-healing, perforated, severe ulcers	7 14 15
Innovative therapies	Address refractory cases	Non-responsive, neurotrophic ulcers	15 16 17

Table 4: Main Treatment Modalities

Antimicrobial Therapy

• Empiric therapy is started immediately after samples are taken for culture. Broad-spectrum antibiotics (often quinolones) are first-line for bacterial ulcers 2 3 5.
• Tailored therapy: Once culture results are available, therapy is adjusted based on the identified organism and its drug sensitivity 3 12.
• Antifungals: Natamycin, amphotericin B, or voriconazole for fungal ulcers 12.
• Antivirals: Topical or systemic acyclovir for HSV ulcers 5.
• Alternative agents: Povidone-iodine 0.66% has shown promise as a broad-spectrum antiseptic when the pathogen is unknown or resistant 3.

Supportive and Adjunctive Therapy

• Lubrication: Artificial tears and ointments to keep the cornea moist and promote healing 6.
• Bandage contact lenses: Protect the ulcerated area and reduce pain 6 7.
• Collagenase inhibitors: Prevent tissue breakdown in severe cases 6.
• Amniotic membrane transplantation: Promotes healing in refractory ulcers and reduces scarring 14.
• Pain control: Cycloplegics and analgesics for symptomatic relief 6.

Surgical Interventions

• Tissue glue and conjunctival flaps: For small corneal perforations or impending perforation 6 7.
• Keratoplasty (corneal transplant): For deep, non-healing, or perforated ulcers 6 7 14.
• Plastic surgery: For persistent aseptic ulcers, including amniotic membrane, scleral, or conjunctival grafts 7 14.

Innovative and Emerging Therapies

• Photo-activated riboflavin (cross-linking): Can halt tissue melting in refractory infectious ulcers, reducing the need for emergency transplant 15.
• Neurotrophic agents: Cenegermin (recombinant human nerve growth factor) and matrix therapy agents support healing in neurotrophic ulcers 16.
• Dual drug-loaded nanofibrous patches: New research shows promise for rapid, controlled antimicrobial delivery 17.

Special Considerations

• Early referral to an ophthalmologist is essential. Delay increases risk of complications and vision loss 1 2.
• Avoid topical steroids in most infectious ulcers, as they can worsen infection, except under specialist guidance 6.
• Address underlying risk factors: Improve contact lens hygiene, treat eyelid disease, and manage systemic illnesses 1 6.

Conclusion

Corneal ulcers are a serious threat to vision but can often be prevented and successfully treated with early recognition and appropriate intervention. Here’s a quick recap:

• Symptoms: Include pain, redness, photophobia, tearing, discharge, and blurred vision. Hypopyon is a severe sign.
• Types: Divided into infectious (bacterial, fungal, viral, parasitic) and non-infectious (neurotrophic, autoimmune, exposure-related), as well as by location and special forms.
• Causes: Most commonly infection (bacterial, fungal, viral, parasitic), trauma, contact lens misuse, autoimmune disease, and nutritional deficiencies.
• Treatment: Rapid antimicrobial therapy, supportive measures, surgical intervention for refractory cases, and emerging therapies are all part of modern management.

Key Takeaways:

• Early diagnosis and treatment are vital to prevent vision loss.
• Risk factors like trauma and poor contact lens hygiene are preventable.
• New therapies are expanding options for difficult-to-treat ulcers.
• Always consult an eye care professional for red, painful eyes that do not improve quickly.

Understanding and acting on the signs and risks of corneal ulcers can save sight—sometimes even with just a day’s difference in seeking care.