Conjunctivitis: Causes, Symptoms, Treatment, and Prevention

~Introduction

Conjunctivitis, commonly known as “pink eye,” is one of the most frequently encountered eye problems worldwide. It is an inflammation of the conjunctiva — the thin, transparent membrane covering the white part of the eye and the inner surface of the eyelids. Although conjunctivitis is usually a mild condition, it can cause significant discomfort, affect daily life, and in some cases, lead to complications if left untreated.

The condition can occur at any age and may result from infections, allergies, irritants, or underlying health issues. Its global prevalence makes it a public health concern, particularly in communities with limited access to healthcare, poor sanitation, and overcrowded living conditions.

This article provides an in-depth discussion of conjunctivitis, including its types, causes, risk factors, symptoms, diagnosis, treatment, complications, and preventive measures.

~Anatomy and Function of the Conjunctiva

To understand conjunctivitis, it is important to know the role of the conjunctiva.

The conjunctiva is a thin, transparent tissue that lines the inside of the eyelids and covers the sclera (the white portion of the eye).
Its main functions are to:
- Lubricate the eye by producing mucus and tears (in small amounts).
- Act as a barrier against microorganisms, dust, and foreign particles.
- Provide immune defense through specialized immune cells.

When this protective tissue becomes inflamed or infected, the result is conjunctivitis.

~Types of Conjunctivitis

Conjunctivitis can be broadly classified based on its cause:

1. Infectious Conjunctivitis

Viral Conjunctivitis
- Caused by adenoviruses, herpes simplex virus, or other respiratory viruses.
- Highly contagious and often spreads through direct contact, contaminated surfaces, or respiratory droplets.
- Frequently associated with colds, sore throat, or respiratory infections.
Bacterial Conjunctivitis
- Caused by bacteria such as Staphylococcus aureus, Streptococcus pneumoniae, or Haemophilus influenzae.
- More common in children but can affect adults as well.
- Characterized by thick discharge and crusting around the eyes.
Fungal Conjunctivitis
- Rare, but may occur after eye trauma, especially with plant material.
- Caused by fungi like Candida or Aspergillus.
Parasitic Conjunctivitis
- Uncommon, but certain parasites (like Onchocerca volvulus, causing river blindness) may involve the conjunctiva.

2. Allergic Conjunctivitis

Triggered by allergens such as pollen, dust mites, pet dander, or mold.
Not contagious.
Common in people with hay fever, asthma, or eczema.
Often seasonal (spring and summer) but may occur year-round.

3. Chemical or Irritant Conjunctivitis

Caused by exposure to chemicals, smoke, chlorine in swimming pools, or air pollution.
Can also result from cosmetics, eye drops, or contact lenses.

4. Neonatal Conjunctivitis (Ophthalmia Neonatorum)

Occurs in newborns, usually within the first month of life.
Caused by infections acquired during birth (e.g., Chlamydia trachomatis or Neisseria gonorrhoeae).
Can be severe and requires immediate treatment to prevent blindness.

~Causes and Risk Factors

Causes

Viruses: Adenoviruses are the most common cause of viral conjunctivitis.
Bacteria: Spread through contact with contaminated hands, towels, or cosmetics.
Allergens: Pollen, dust, animal fur, and certain eye drops.
Chemical irritants: Smoke, chlorine, industrial chemicals.
Contact lenses: Poor hygiene, prolonged use, or improper cleaning can cause irritation or infection.

Risk Factors

Children in schools or daycare (due to close contact).
People with weak immune systems.
Individuals with seasonal allergies.
Those living in crowded or unsanitary environments.
Frequent users of contact lenses.

~Symptoms of Conjunctivitis

The symptoms vary depending on the type, but general signs include:

Redness of the eye (due to inflamed blood vessels).
Itching or irritation.
Watery eyes (common in viral and allergic conjunctivitis).
Discharge:
- Watery or mucous-like in viral conjunctivitis.
- Thick yellow or greenish discharge in bacterial conjunctivitis.
Crusting of eyelids, especially after sleep.
Swollen eyelids.
Sensitivity to light (photophobia).
Foreign body sensation (feeling like something is in the eye).
In allergic conjunctivitis, both eyes are usually affected, along with sneezing and nasal congestion.

~Diagnosis of Conjunctivitis

Diagnosis usually involves a clinical examination by an ophthalmologist or healthcare provider.

Methods of Diagnosis:

Medical History: Recent illnesses, allergies, exposure to irritants, or contact with infected individuals.
Physical Examination: Redness, discharge, swelling, and other signs.
Laboratory Tests (in severe or recurrent cases):
- Swab of eye discharge for bacterial culture.
- Polymerase Chain Reaction (PCR) test for viral causes.
- Allergy tests for allergic conjunctivitis.

~Treatment of Conjunctivitis

1. Viral Conjunctivitis

Usually self-limiting (resolves in 1–2 weeks).
Treatment focuses on relief of symptoms:
- Cold compresses.
- Artificial tears (lubricating eye drops).
- Antiviral medication (in severe cases, e.g., herpes simplex).
Patients are advised to stay home to prevent spreading.

2. Bacterial Conjunctivitis

Treated with antibiotic eye drops or ointments (such as chloramphenicol, ciprofloxacin, or erythromycin).
Improvement is usually seen within 2–3 days.

3. Allergic Conjunctivitis

Avoidance of allergens is the first step.
Medications include:
- Antihistamine eye drops (e.g., olopatadine).
- Mast cell stabilizers.
- Corticosteroid drops (only for severe cases and under medical supervision).

4. Chemical/Irritant Conjunctivitis

Immediate rinsing of the eyes with clean water or saline solution.
Medical treatment for severe chemical burns.

5. Neonatal Conjunctivitis

Requires urgent treatment with appropriate antibiotics or antivirals.
Preventive use of antibiotic eye drops is often given to newborns in some countries.

~Complications of Conjunctivitis

Although conjunctivitis is usually mild, complications can occur:

Chronic conjunctivitis (persistent or recurring).
Corneal involvement (keratitis), leading to vision problems.
Scarring of the conjunctiva in severe cases.
In newborns, untreated infections can cause blindness.

~Prevention of Conjunctivitis

Prevention focuses on hygiene, avoidance of allergens, and protective measures.

General Preventive Steps:

Wash hands frequently with soap and water.
Avoid touching or rubbing the eyes.
Do not share towels, pillows, cosmetics, or eye drops.
Replace eye makeup regularly and avoid using old products.
Follow proper contact lens hygiene:
- Wash hands before handling lenses.
- Clean and store lenses properly.
- Avoid sleeping in lenses unless prescribed.
Wear protective eyewear when swimming (to avoid chlorine irritation).
Maintain good air quality and avoid exposure to smoke or dust.

Public Health Measures:

Isolation of infected individuals in schools or workplaces to reduce outbreaks.
Education about hygiene in communities with poor sanitation.
Regular screening in high-risk populations (e.g., children, newborns).

~Prognosis

Most cases of conjunctivitis resolve without long-term consequences.
Viral cases may take longer but usually heal on their own.
Allergic conjunctivitis may persist or recur depending on allergen exposure.
Early treatment ensures a good outcome in bacterial and neonatal cases.

~Conjunctivitis in the Context of Public Health

Conjunctivitis, although generally not life-threatening, poses a burden due to:

High prevalence and frequent outbreaks.
School and work absenteeism.
Potential complications if untreated.
Need for antibiotic stewardship (to avoid resistance).

Health education, hygiene promotion, and timely medical care play vital roles in reducing the burden.

~Conclusion

Conjunctivitis, or “pink eye,” is a common but manageable eye condition. Its various forms — viral, bacterial, allergic, or irritant — share common symptoms like redness, discharge, and discomfort, but differ in treatment approaches. While most cases resolve without complications, untreated or severe forms can cause long-term damage.

Prevention through hygiene, responsible use of contact lenses, avoidance of allergens, and public health measures is crucial. With timely diagnosis and proper treatment, conjunctivitis can be effectively controlled, ensuring minimal disruption to daily life and safeguarding vision health.

Health Lines

Monday, August 25, 2025