Conjunctivitis

Dr Ben Wild

Overview

The conjunctiva is a clear layer of tissue that extends from the edge of the cornea, around the visible portion of the eye in front of the white sclera, and even the back surface of the eyelids. It posses as a barrier against foreign material and contributes to proper lubrication and tears.

Frontal view of a healthy eye.

Conjunctivitis, commonly referred to as “pink eye”, represents inflammation of the conjunctiva caused by either bacterial, chlamydial, and/or viral infections, allergies or others causes.

Bacterial conjunctivitis occurs after contact with bacteria via other eyes or genitals. It begins unilaterally (in one eye) but transmission to the fellow eye 1-2 days later is common.

Chlamydial conjunctivitis can spread eye to eye but often is spread via the genitals. It can be unilateral or bilateral and tends to take months to resolve unless properly treated.

Viral conjunctivitis is most often caused by adenoviruses (90% of the time) or herpes simplex type 1 (HSV) aka the cold sore virus. It can range from mild to severe, starts unilaterally (in one eye) then becomes bilateral (both eyes) but is almost exclusively unilateral with HSV, and is often accompanied by a fever and sore throat. HSV often presents alongside skin vesicles on the eyelid. Other viruses include mumps, measles, shingles, HIV, COVID, etc.

Allergic conjunctivitis is common and occurs after or during exposure to an allergen. Severe forms of allergic conjunctivitis include atopic and vernal keratoconjunctivitis. Atopic tends to develop in adulthood, symptoms tend to be more severe and is associated with eczema and asthma whereas vernal tends to affect primarily young boys and can resolve.

Frontal view of an eye with severe conjunctivitis.

Signs and Symptoms

Signs

Common to all: eye redness

Bacterial	Small bumps on the inner eyelids.
​Chlamydia	​Large bumps on the inner eyelids, scarring of the conjunctiva.
Viral	Large bumps on the inner lids, lid swelling, broken blood vessels on conjunctiva, membranes forming under eyelid, skin nodules.
Allergic	​Swelling of eye and/or lids, sneezing, nasal discharge, small bumps on inner lids, white bumps on the eye.

Symptoms

Common to all: tearing, grittiness, stinging, burning, light sensitivity

Bacterial	Eyes stuck shut in the morning, milky/yellow discharge.
Chlamydia	Tender lymph nodes, mucous discharge.
Viral	Tender lymph nodes, watery discharge.
Allergic	Watery to mucousy discharge.

Causes and Risk Factors

Causes

Infection of the conjunctiva.

Risk Factors

Exposure to bacteria, chlamydia, viruses or allergens, immunosuppressant use, any ocular trauma.

Prevention and Treatment

Prevention

Hygiene including washing the eyelids everyday and washing hands throughout the day.

Treatments

Common with all conjunctivitis: discontinue contact lens wear, reduce transmission risk by washing hands often and all pillow cases, towels, etc. that contact the face.

Bacterial	Antibiotic drops or pills, steroid drops, referral to genitourinary specialist.
Chlamydia	Azithromycin or doxycycline antibiotic pills, erythromycin drops, referral to genitourinary specialist.
Viral	Steroid drops when not HSV, antiviral pills when HSV, artificial tears, cold compresses, decongestants
Allergic	Artificial tears, cold compresses, antihistamine/mast cell stabilizer drops or pills, steroid or non steroidal anti-inflammatory drops, cyclosporin drops

Prognosis

Conjunctivitis is usually easily managed by the treatments listed above. However, it can leave permanent scarring to the eye which can be vision threatening if not treated. It can also be easily transmissible. Protecting others by decreasing transmission risk is essential.