Overview

Keratoconjunctivitis is a bacterial infectious condition that leads to swelling of the outer layer of the eyeball. The term keratoconjunctivitis refers to the inflammation of two distinct parts of the eye: the cornea (keratitis) and the conjunctiva (conjunctivitis).¹ Keratitis is the swelling of the cornea, which is located in front of a fluid-filled area known as the anterior chamber that surrounds the iris and pupil.² Conjunctivitis is the swelling of the conjunctiva, the transparent membrane that covers the sclera (the white part of the eye). Keratoconjunctivitis is a combination of both keratitis and conjunctivitis, resulting in inflammation, itching, discomfort, visual impairment, and redness in the eyes.¹ Some common species that cause keratoconjunctivitis are Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa.^3,4

Early detection and treatment of keratoconjunctivitis are important to reduce further complications. Delays in treatment may result in corneal ulcers, perforation, and vision loss. Additionally, because it is highly contagious, early detection can help minimise the spread of the disease. This article will discuss the symptoms, diagnosis, and treatment of this condition. Symptoms: 

Symptoms of bacterial keratoconjunctivitis include: 

• Eyes are red
• Eyes itching
• Watery discharge
• Blurred vision
• Light sensitivity  (photophobia)
• Difficulty opening the eyelid due to pain and irritation

Diagnosis

Accurate diagnosis is essential for effective treatment and preventing complications in eye care. The diagnostic process begins with a thorough clinical assessment, which includes detailed history taking and various clinical evaluations.

1. History taking

A comprehensive history is essential to understand the patient's symptoms, including onset and duration, contact lens use, history of eye surgery or trauma, and exposure to infections.

2. Clinical examination

A clinical evaluation for keratoconjunctivitis involves assessing symptoms, conducting a thorough eye exam, and potentially running tests to identify the underlying cause. The most common clinical evaluation tests for keratoconjunctivitis include:

Penlight exam

Eye care professionals will use a penlight to assess your pupils for their reaction, size, and additional characteristics. They may also apply a stain to your eyes to identify any damage to the corneal surface.⁵ 

Slit lamp exam 

Eye care professionals will examine your eyes with a special instrument called slit lamp. A slit lamp examination is a microscopic evaluation of your eyes with a bright source that gives a 3D view of the front and back structures of your eyes.⁵

Schirmer test

This test measures tear production to assess for dry eye. Eye care professionals will place a small strip of filter paper under your lower eyelid for a few minutes to assess how much tears are produced. The test helps determine if your eyes produce enough tears to keep them moist, which is crucial for maintaining eye health and comfort.⁶

Tear break-up time (TBUT) test

TBUT is a diagnostic tool used by eye care professionals to assess the stability of the tear film on the surface of the eye, which can indicate dry eye syndrome. During the test, eye care professionals will apply a fluorescein dye to the eye, and the doctor will observe the tear film using a slit lamp with a blue light to see how long it takes for the tears to break up after a blink.⁶

Laboratory test    

The main diagnostic tool for keratoconjunctivitis is a Gram stain and culture of corneal samples. While Gram stains are not perfectly sensitive, detecting between 60 to 75% of bacteria, they are a crucial first step. For bacterial cultures, blood and chocolate agar are used to promote growth. Once bacteria are identified, specific treatments can be administered.  

Treatment

The treatment of keratoconjunctivitis involves both medical and supportive care, with the specific approach depending on the underlying cause.

Medical care

Topical antibiotics are always the first line of treatment for bacterial keratoconjunctivitis. When selecting an antibiotic regimen, factors such as broad spectrum coverage, potential toxicity, cost, and availability should be considered. A recent international survey revealed that US clinicians tend to favour fortified antibiotics over international sites when treating bacterial keratoconjunctivitis.⁸   

What are fortified antibiotics? 

Fortified antibiotics are prepared in compounding pharmacies to provide high-concentration eye drops for the treatment of severe infections. US clinicians use fortified vancomycin due to concerns about antibiotic resistance and to target infections caused by methicillin-resistant S. aureus (MRSA).⁷ Other fortified antibiotics, like tobramycin and gentamicin, are used for gram-negative bacteria. Linezolid is suggested as a less toxic alternative to vancomycin while still covering MRSA.

Fluoroquinolone monotherapy

Fourth-generation fluoroquinolones, such as moxifloxacin and gatifloxacin, are used when fortified antibiotics are unavailable and are noted for their broad-spectrum activity and ability to penetrate tissues.⁸ They are particularly useful against gram-positive bacteria, often showing better activity in vitro than earlier fluoroquinolones like ciprofloxacin or ofloxacin.⁹

A recent Cochrane-style review found that there was no significant difference in treatment success or recovery time between different topical antibiotic combinations. However, the review did observe a higher risk of minor side effects, like eye discomfort or conjunctivitis, when using aminoglycoside-cephalosporin combinations compared to other treatments.¹⁰

Anti-collagenases

During an acute infection, various inflammatory cells, including fibroblasts and keratocytes, produce enzymes like collagenases that play a role in the breakdown of proteins and keratolysis, resulting in several complications, such as corneal perforation. 

Tetracyclines have been shown to inhibit collagenase activity.¹¹ For instance, one study showed that the incidence of alkali-induced corneal perforation in rabbits was dramatically reduced from 85% to 9% with the administration of high-dose systemic tetracyclines.¹² 

In cases of keratoconjunctivitis, particularly when corneal melting is a concern, anti-collagenase treatments, such as tetracyclines, may be used to inhibit collagen breakdown and stabilise the cornea.

Steroids

The use of corticosteroids in treating bacterial keratoconjunctivitis is a subject of debate due to conflicting evidence regarding their benefits and risks.. While some argue that corticosteroids can reduce inflammation and scarring, others express concern about potential harm to epithelial healing and increased risk of infection.¹³

Surgical care

Bacterial corneal perforation, occurring in 25-45% of bacterial corneal infections, requires surgical intervention depending on the severity. Treatment options include:

• Penetrating keratoplasty (corneal transplant)
• Sclerocorneal patches (small damage)
• Cyanoacrylate adhesive (to seal small perforations)

Supportive care

Some supportive care for eye issues includes:

• Cycloplegic eye drops: These drops, such as atropine, help relax the muscle spasm, reduce eye pain and decrease photophobia
• Artificial tears: These drops are used to soothe the ocular surface, maintain corneal moisture, and support epithelial healing 
• Eye protection: Protect the eyes with eye shields such as sunglasses
• Avoid rubbing the eyes
• Cleanliness: Use a clean towel and pillow for your eyes
• Nutritional support: Vitamins A and C are important for tissue repair and can be supplemented to aid the healing process. Monitoring: Regular check-ups are essential to keep your doctor updated

Prevention

Prevention strategies are crucial to reduce the risk of infections, recurrence and transmission. Some preventive measures are:

• Maintain personal hygiene
• Avoid touching and rubbing your hands
• Avoid sharing towels, pillows, and cosmetics
• Use contact lenses properly, and don't use tap water for lenses
• Avoid contact with infectious patients

FAQs

Is bacterial keratoconjunctivitis contagious? 

Yes, it is contagious. It is transferred through direct contact with eye secretion, contaminated hands, towels, etc.

Can I wear contact lenses while treatment?

No, you can't wear contact lenses until the infection is completely cured or the doctor gives you clearance.

How long does it take to heal? 

With proper treatment, it takes 10 to 15 days. If the condition is severe,  it may take a longer time.

When should I see a doctor urgently?

Seek immediate care if you experience:

• Severe pain
• Vision loss
• Light sensitivity
• No improvement within 48–72 hours of starting antibiotics

How can I prevent bacterial keratoconjunctivitis?

Maintain good hand hygiene, properly disinfect contact lenses, and avoid sharing personal items like towels or makeup.

Summary

Keratoconjunctivitis is an inflammation of the outer layer of the eyeball. It is a combination of two diseases: keratitis and conjunctivitis. Keratitis means the inflammation of the cornea, and conjunctivitis means the inflammation of the conjunctiva. Early detection is essential for the prevention of further complications.

Eye care providers can easily diagnose keratoconjunctivitis through symptoms such as eye irritation, watery discharge, or blurred vision with diagnostic techniques such as the use of a penlight orslit lamp. Treatment may include antibiotics, anti-collagenase agents, surgery, and supportive care, with the specific approach tailored to the underlying cause.