Inflammation of the conjunctiva, most common cause of a red eye

Clinical features

• Inflammation - swelling, redness, pain, heat
• Gritty irritation/itchiness
• Watery/purulent discharge
• Does not cause pain, photophobia or reduced visual acuity

Investigations

• If suspect infective aetiology, swab for culture - bacterial, chlamydial, viral

Viral conjunctivitis

• Most common cause

Causative organisms

• Adenovirus (most common)
• Herpes simplex
• Herpes zoster

Clinical features

• Sudden onset, rapidly progressive
• Typically bilateral, often manifests in one eye before spreading to the other
• Some patients will have associated URT - dry cough, sore throat and blocked nose
• Adenoviral - watery discharge
• Herpes simplex - cutaneous vesicles develop on the eyelids and on the skin around the eyes