Tuesday, October 16, 2012

CONJUNCTIVITIS

Conjunctivitis is an inflammation of the outer surface (cornea) of the eye, due to an allergy, or a viral or bacterial
infection.
A bacterial conjunctivitis  is  the most common  form, and  is due  to bacteria  infecting  the  thin  film of  tears  that
covers the eye. It is very easily passed from one person to another (eg. a patient rubs their eyes with a hand, then

shakes hands, and the second person then rubs their eyes). Babies suffering from a blocked tear duct may have
recurrent  infections. Tears are produced  in  the  lacrimal gland beyond  the outer edge of  the eye, move across  the
eye surface and then through a tiny tube at the inner edge of the eye that leads to the nose. If the duct is too small
in an infant, or is blocked by pus or phlegm, the circulation of tears is prevented and infection results.
Any one or more of a number of viruses may infect the cornea to cause conjunctivitis. This form is not quite as
easily transmitted as bacterial conjunctivitis.
Bacterial  conjunctivitis  causes  the  formation of  yellow or green pus  in  the eyes, which may  stick  the eyelidstogether. The eyes are bloodshot and  sore, and almost  invariably  the  infection  involves both eyes.  If allowed  to
persist, it may cause scarring of the eye surface and a deterioration in sight.
Viral conjunctivitis causes slight pain or an itch, redness of the eye and often a clear sticky exudate. 
Rarely,  resistant  infections make  it necessary  to  take a swab  from  the eye  to determine  the exact bacteria or
virus responsible, but in most cases, no investigations are necessary.
Bacterial  conjunctivitis  is easily  treated with antibiotic drops or ointment on a  regular  basis  until  the  infection
clears, usually  in  two  to  four days. Children must be excluded  from school until all eye discharge has ceased. A
blocked tear duct may be probed and cleared if
conjunctivitis  persists  in  a  baby  for  several
months, but most grow out of the problem.
Viral  conjunctivitis  is  the more  difficult  form
to  treat  as  there  is  no  cure  for  most  viral
infections,  but  Herpes virus infections can be
cured  by  antiviral  drops.  Soothing  drops  and
ointment  may  be  used,  but  time  is  the  main
treatment,  and  the  infection  may  persist  for
several  weeks  until  the  body's  own  defences
overcome it.
Allergic  (vernal)  conjunctivitis  is  a  reaction
on  the  surface  of  the  eye  to  a  pollen,  dust,
chemical or substance to which the patient has
an  allergy.  The  eye  becomes  red,  itchy  and
watery.  Vasoconstrictor  or  antihistamine  eye
drops can be used to control the condition.
See also ALLERGIC CONJUNCTIVITIS

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