VIRAL CONJUNCTIVITIS

Most of the viral infections tend to affect the epithelium, both of the conjunctiva and cornea, so, the typical viral lesion is a 'keratoconjunctivitis'. In some viral infections, conjunctival involvement is more prominent (e.g., pharyngo-conjunctival fever), while in others cornea is more involved (e.g., herpes simplex).

Viral infections of conjunctiva include:

• Adenovirus conjunctivitis
• Herpes simplex keratoconjunctivitis
• Herpes zoster conjunctivitis
• Pox virus conjunctivitis
• Myxovirus conjunctivitis
• Paramyxovirus conjunctivitis
• ARBOR virus conjunctivitis

Clinical presentations. Acute viral conjunctivitis may
present in
three 
clinical forms:
1. Acute serous conjunctivitis
2. Acute haemorrhagic conjunctivitis
3. Acute follicular conjunctivitis

ACUTE SEROUS CONJUNCTIVITIS
Etiology. It is typically caused by a mild grade viral
infection which does not give rise to follicular
response.

Clinical features. Acute serous conjunctivitis is
characterised by a minimal degree of congestion, a
watery discharge and a boggy swelling of the conjunctival mucosa.

Treatment. Usually it is self-limiting and does not
need any treatment. But to avoid secondary bacterial
infection, broad spectrum antibiotic eye drops may
be used three times a day for about 7 days.

ACUTE HAEMORRHAGIC CONJUNCTIVITIS
It is an acute inflammation of conjunctiva characterised by multiple conjunctival haemorrhages, conjunctival hyperaemia and mild follicular
hyperplasia.

Etiology. The disease is caused by picornaviruses (enterovirus type 70) which are RNA viruses of small (pico) size. The disease is very contagious and is
transmitted by direct hand-to-eye contact.

Clinical picture. The disease has occurred in an
epidemic form in the Far East, Africa and England and
hence the name 'epidemic haemorrhagic conjunctivitis
(EHC)' has been suggested. An epidemic of the
disease was first recognized in Ghana in 1969 at the
time when Apollo XI spacecraft was launched, hence
the name 'Apollo conjunctivitis'.

• Incubation period of EHC is very short (1-2 days).
• Symptoms include pain, redness, watering, mild photophobia, transient blurring of vision and lid swelling.
• Signs of EHC are conjunctival congestion, chemosis, multiple haemorrhages in bulbar conjunctiva, mild follicular hyperplasia, lid oedema and pre-auricular lymphadenopathy.
• Corneal involvement may occur in the form of fine epithelial keratitis.

Treatment. EHC is very infectious and poses major
potential problems of cross-infection. Therefore,
prophylactic measures are very important. No specific
effective curative treatment is known. However, broad
spectrum antibiotic eye drops may be used to prevent
secondary bacterial infections. Usually the disease
has a self-limiting course of 5-7 days.

FOLLICULAR CONJUNCTIVITIS
It is the inflammation of conjunctiva, characterised
by formation of follicles, conjunctival hyperaemia and
discharge from the eyes. Follicles are formed due to
localised aggregation of lymphocytes in the adenoid
layer of conjunctiva. Follicles appear as tiny, greyish
white translucent, rounded swellings, 1-2 mm in
diameter. Their appearance resembles boiled sagograins.
Types (discussed later in other posts)
1. Acute follicular conjunctivitis.
2. Chronic follicular conjunctivitis.
3. Specific type of conjunctivitis with follicle
formation e.g., trachoma