Red Eye: Summaries of Key Conditions

Below is an overview of optic neuritis, uveitis, herpes ophthalmicus, and various types of conjunctivitis, including their clinical features, investigations, and management strategies.

1. Optic Neuritis

Pathology

• Inflammation of the optic nerve often associated with multiple sclerosis or autoimmune/infectious aetiologies (sarcoidosis, neuromyelitis optica).

Features

• Monocular vision loss: Central scotoma, colour desaturation (especially red).

• Pain: Worsening with extraocular movements (90% cases).

• Afferent pupillary defect (Marcus Gunn pupil).

Management

• Urgent referral to neurologist/ophthalmologist.

• High-dose IV corticosteroids (e.g. methylprednisolone).

• MRI to evaluate for MS or demyelinating lesions.

2. Uveitis

Pathology

• Inflammation of the uveal tract (iris, ciliary body, choroid).

• Linked to autoimmune (IBD, ankylosing spondylitis) or infectious (TB, syphilis, HSV) causes.

Features

• Anterior Uveitis (Iritis):

  • Painful red eye, ciliary/perilimbal injection, photophobia, blurred vision.

  • Severe cases: Hypopyon (layer of WBCs in anterior chamber).

• Posterior Uveitis:

  • Often painless, presents with floaters, visual field defects, blurred vision.

Management

• Urgent ophthalmology referral.

• Anterior: Topical steroids (e.g. prednisolone acetate), cycloplegics (e.g. atropine).

• Posterior/recurrent: Systemic steroids or immunosuppressants.

3. Herpes Ophthalmicus

Pathology

• Varicella Zoster Virus reactivation in the ophthalmic branch (V1) of CN V.

• Can cause corneal ulceration, scarring, vision loss if untreated.

Features

• Painful red eye, vesicular rash in V1 distribution (forehead, scalp, nose).

• Hutchinson’s sign: Vesicle on tip/side of nose → high risk of ocular involvement.

• Photophobia, decreased vision, possible corneal dendritic ulcers.

Management

• Oral antivirals (within 72 hrs):

  • Valaciclovir 1 g TDS or aciclovir 800 mg 5×/day for 7–10 days.

• Lubricants for comfort.

• Urgent ophthalmology referral if ocular involvement.

• Avoid topical antivirals unless directed; topical steroids only after ophthalmology review.

Conjunctivitis (Red Eye)

General Management

• Emphasise hygiene: Avoid eye rubbing, sharing towels, contact lenses.

• Saline bathing can soothe symptoms.

• Swab for suspected herpes simplex, chlamydia, gonorrhoea, or if treatment failure.

• Urgent referral if severe pain, photophobia, or reduced vision.

Viral Conjunctivitis

• Features: Gritty/burning sensation, watery discharge, preauricular lymphadenopathy (common with adenovirus).

• Management: Cool compresses, lubricating drops, symptomatic relief; highly contagious.

Allergic Conjunctivitis

• Features: Itchy, burning eyes, sneezing, watery rhinorrhoea (often associated with asthma/eczema).

• Management:

  • Avoid allergens, compresses.

  • Topical antihistamine drops (e.g. azelastine).

  • Oral antihistamines, nasal steroids for systemic symptoms.

Bacterial Conjunctivitis

• Features: Purulent discharge, redness, often bilateral.

• Management:

  • Chloramphenicol 0.5% drops 1 drop QID × 7 days (or framycetin).

  • Swab if persistent or atypical.

  • Gonococcal: Ceftriaxone 1 g IM.

Neonatal Conjunctivitis

• Causes:

  • Chlamydia: Onset ~1–2 weeks post-delivery, purulent discharge.

  • Gonococcal: Severe discharge, early onset (ophthalmic emergency).

• Management:

  • Chlamydia: Azithromycin 20 mg/kg PO × 3 days.

  • Gonococcal: Ceftriaxone 1 g IM.

  • Treat household contacts; ensure regular hygiene.

Notes and Takeaways

• Posterior Uveitis: Systemic workup for infectious/autoimmune causes.

• Herpes Ophthalmicus: Steroids only after starting antivirals.

• Preauricular Lymphadenopathy: Suggestive of viral conjunctivitis.

• Neonatal gonococcal conjunctivitis → risk of corneal perforation, urgent referral.