Viral Diseases of the Eye — Questions

Tests. Check the CD4 count and HIV viral load (corticosteroid for IRIS implies recent immune status), arrange fundoscopy, and confirm with PCR of ocular fluid (and blood) for CMV.

Diagnosis. The most likely diagnosis is CMV retinitis, unmasked by profound immunosuppression; steroid for IRIS may have worsened it.

Management. Treat with ganciclovir or oral valganciclovir (systemic, with intravitreal therapy if sight-threatening), and continue and optimise antiretroviral therapy to restore immunity; review the steroid.

Complications. Treatment and immune recovery carry the risk of immune recovery uveitis, and the retinitis itself can lead to retinal detachment and permanent visual loss in the long term.

Diagnosis. Herpes zoster ophthalmicus, reactivation of varicella-zoster virus in the ophthalmic division of the trigeminal nerve. The vesicle on the tip of the nose (Hutchinson’s sign) indicates nasociliary involvement and predicts ocular disease.

Indications for antiviral treatment. Systemic aciclovir, valaciclovir or famciclovir, started within 72 hours of rash onset, which hastens healing and reduces ocular complications. Treatment is also indicated in any ocular involvement, older or immunosuppressed patients, with intravenous aciclovir for the immunosuppressed to prevent dissemination.

• Adenoviral conjunctivitis is highly contagious and spreads by hands, secretions and contaminated surfaces and objects.
• Advise frequent handwashing by the child and classmates, and avoiding touching or rubbing the eyes.
• Keep the affected child at home until the discharge settles, as shedding continues for up to two weeks.
• Do not share towels, face cloths, toys or other items, and clean shared surfaces, since the virus survives on surfaces.

The virus is adenovirus, the commonest cause of viral conjunctivitis. Its ocular syndromes are:

• Pharyngoconjunctival fever (fever, sore throat and conjunctivitis).
• Epidemic keratoconjunctivitis (a highly contagious keratoconjunctivitis).
• Nonspecific follicular conjunctivitis (mild, self-limiting, the commonest form).
• Chronic keratoconjunctivitis (rare, with prolonged irritation).

The dendritic ulcer is the classic epithelial lesion of herpes simplex keratitis, best seen with fluorescein.

The other viruses cause different corneal pictures.

A variant of coxsackievirus A24 and enterovirus 70 cause acute haemorrhagic conjunctivitis, an explosive, self-limiting conjunctivitis with subconjunctival haemorrhages.

Adenovirus 8 and 19 cause epidemic keratoconjunctivitis, not the haemorrhagic form.

Adenovirus is non-enveloped, resists disinfection and survives on instruments and surfaces, so it spreads readily in eye clinics through contaminated equipment.

It is not vector-borne or long-range airborne, and it infects the immunocompetent.

CMV retinitis occurs at a CD4 count below about 50 cells per cubic millimetre, in advanced immunosuppression.

Higher counts are not the typical threshold for CMV retinitis.

Ganciclovir or its oral prodrug valganciclovir is first-line, with foscarnet or cidofovir as alternatives, alongside antiretroviral therapy.

Aciclovir is too weak against CMV, and the other agents are for different viruses.

Hutchinson’s sign reflects involvement of the nasociliary branch of the trigeminal nerve and predicts ocular disease in about half of cases.

It is not a sign of benign disease, superinfection, dissemination or resolution.

CMV retinitis shows a “pizza-pie” fundus of necrosis and haemorrhage, with owl’s eye intranuclear inclusions histologically.

Cotton-wool spots suggest HIV retinopathy, and salt-and-pepper retinopathy congenital rubella.

Congenital rubella causes cataract, a salt-and-pepper pigmentary retinopathy, glaucoma and microphthalmia.

The other findings belong to CMV, HSV, enterovirus and HHV-8 respectively.

Measles is the commonest viral cause of childhood blindness in developing countries, causing keratomalacia and corneal ulceration where vitamin A deficiency coexists; vitamin A is a treatment priority.

The other viruses are not the leading cause of childhood corneal blindness.

Stromal keratitis is the commonest sight-threatening manifestation, an immune-mediated reaction that scars the cornea and may require a graft.

The other manifestations rarely threaten sight.

Adenovirus is the commonest cause of viral conjunctivitis and of eye-clinic epidemics.

The others cause conjunctivitis less often or in specific settings.

PCR of the aqueous or vitreous fluid is the most sensitive method, more so than culture or antigen detection; intraocular antibody production can be quantified by the Goldmann-Witmer coefficient.

The other methods are less sensitive for intraocular infection.

Steroids let the virus replicate freely, enlarging a dendritic ulcer into a geographical ulcer, so they are never used alone for epithelial keratitis; under antiviral cover they help control stromal inflammation.

They neither cure nor prevent scarring when used alone.