VIRAL CONJUNCTIVITIS This is usually caused by adenoviruses (epidemic keratoconjunctivitis and pharyngoconjuncti- val fever) or herpes simplex, less frequently by varicella-zoster virus, picornaviruses, pox and papilloma viruses. The infections are transmitted by hand to eye contact, contact with upper respiratory tract droplets, infected swimming pools or infected ocular instruments like tono- meters. Typical signs of viral conjunctivitis are conjuncti- val hyperaemia, copious, clear, serous, watery discharge, lid oedema and follicular conjunctival reaction. (Figure 3 and 4) It follows a longer course than bacterial conjuncti- vitis, usually 2 – 3 weeks. Preauricular lymph nodes are usually involved. Sometimes a history of recent fever,
upper respiratory tract infections or pharyngitis helps to establish diagnosis. 
Figure 3 – Intensive conjunctival hyperae- mia in epidemic adenoviral keratoconjunc- tivitis.
Adenoviral infections are usually highly contagious and occur in epidemics. Patients usually give a history of recent exposure to an individual with red eye at home or work. The onset of infection is abrupt and the second eye is involved in 1 – 2 days. The disease usually presents with significant conjunctival injection, copious, clear, watery, serous discharge, eyelid oedema and follicular conjuncti- val reaction.  Distinctive signs of adenoviral infection are: follicular conjunctivitis with abrupt onset, watery discharge, lid oedema, subepithelial corneal infiltrates and preauricular lymph node enlargement. [13, 15] Patients with adenoviral conjunctivitis are contagious to others for three weeks after the beginning of the infec- tion.  Subtypes of adenoviral conjunctivitis include epi- demic keratoconjunctivitis (EKC) and pharyngoconjuncti- val fever (PCF).
Figure 4 – Typical follicular reaction in lower palpebral conjunctiva in viral con- junctivitis
Figure 5 – Small, round, grayish, subepi- thelial infiltrates in the cornea of patients with epidemic keratoconjunctivitis.
a. Epidemic keratoconjunctivitis (EKC) is characterized by a sudden onset of signs and symptoms; significant irrita- tion, soreness, red eye, photophobia, foreign body sen- sation, and excessive watery discharge. Marked eyelid swelling and erythema is often present. In severe cases, conjunctival membranes, pseudomembranes and subcon- junctival haemorrhages and chemosis may develop. A typical complication of EKC is the development of small, round, grayish subepithelial infiltrates in the cornea. (Figure 5) They appear about two weeks after the onset of the conjunctivitis and may persist for weeks to months, sometimes to years, eventually resolving spontaneously without scarring. They may decrease visual acuity and cause glare. Preauricular lymph nodes are usually enlar- ged. Sometimes, concurrent upper respiratory tract infec- tion is observed.
b. Pharyngoconjunctival fever (PCF) is characterized by fever, pharyngitis, acute follicular conjunc- tivitis and regional lymphoid hyperplasia with tender, enlarged preauricular adenopathy. Usually, clinical signs and symptoms are less severe than in EKC and corneal involvement is rare. 
Herpes simplex conjunctivitis is caused by HSV type 1. In neonates, infection is due to mater- nal genital infection with HSV-2. Conjunctival signs are typical for viral conjunctivitis but some- times a vesicular eyelid rash may accompany herpetic conjunctivitis and is a distinctive sign of this infection. It is often associated with corneal involvement. A typical manifestation is dendritic keratitis with the typical pictu- re of linear branching lesions. (Figure 6 and Figure 6, Chapter III) Other forms of corneal involvement are less frequent (epithelial keratitis, neurotrophic keratopathy, interstitial keratitis, necrotizing stromal keratitis, disci- form stromal keratitis, endotheliitis). Preauricular lymph nodes are usually involved. Fever and upper respiratory tract infections may precede or accompany herpes sim- plex conjunctivitis. Distinctive signs of herpetic infection are: vesicular eyelid rash and dendritic epithelial keratitis. [1, 13] Figure 6 – Typical picture of linear bran- ching figures of epithelial corneal lesions (dendritic keratitis) in herpetic keratitis
Varicella-zoster conjunctivitis is caused by varicella-zoster virus (VZV) and is unilateral. It is cha- racterized by typical vesicular skin eruptions involving the tissues innervated by the ophthal- mic division of the trigeminal nerve (eye, ear, mouth, tongue, skin), fever, headache, signifi- cant ocular pain and sometimes extraocular signs and symptoms (hyperaesthesia, pain in the affected dermatome, vertigo, hearing loss, taste alteration, paralysis of the facial nerve).  Conjunctivitis is associated with corneal involvement in 40 – 60 % of the cases, iridocyclitis in up to 40 % and elevated IOP in 40 %. These complications usually cause a decrease in visual acuity. Recurrence is a characteristic feature of herpes zoster ophthalmicus. A vesicular eyelid and face rash and significant pain that accompany varicella-zoster infection is a distinctive sign of this infection. 
Acute haemorrhagic conjunctivitis is caused by picornaviruses and has been described in Egypt and other African countries, China, India, Japan and Cuba. As EKC it is a rapidly progressive and highly contagious infection. Its signs include swollen lids, conjunctival follicles, chemosis
and typical subconjunctival haemorrhages, which can range from petechiae to coalescent,
large areas of haemorrhages.  Superficial epithelial changes can be seen sometimes in the cornea. The infection usually resolves without sequellae. In infants and children, polio-like paralysis, aseptic meningitis and involvement of different organ systems, ranging from the myocardium to the CNS, respiratory system and skin, have been described.
Molluscum contagiosum is a cutaneous or conjunctival pox viral infection that causes a raised, waxy, umbilicated lesion on the eyelids, near the lid margin and face. An immunocompromi-
sed state may predispose to multiple and/or large lesions.  Virus particles that are shed into the tear film from eyelid lesions may cause a reaction of the conjunctiva and cornea, resulting
in a chronic, follicular conjunctivitis and sometimes punctate corneal epithelial defects with subepithelial corneal opacities and mild superior keratitis. Conjunctivitis is usually unilateral