Pink Eye is an inflammation of the conjunctiva (the outermost layer of the eye and the inner surface of the eyelids, technically known as "infections conjunctivitis"). There are two common varieties of infections conjunctivitis, viral, and bacterial.
Viral conjunctivitis, "viral pink eye" is due to spread by aerosol or contact of a variety of contagious viruses, including many that cause the 'common cold', so that it is often associated with upper respiratory tract symptoms. Large groupings of cases have been due to transfer on ophthalmic instruments which make contact with the eye and not adequately sterilised.
Bacterial conjunctivitis, "bacterial pink eye" is most often caused by pyogenic bacteria such as Staphylococcus or Streptococcus from the patient's own skin or respiratory flora. Others are due to infection from the environment or from other people, usually by touch (especially in children), but occasionally via eye makeup or facial lotions.
pink eye symptoms
The main three symptoms of pink eye can be summarized as:
- Watering of the eyes
These symptoms are common to all forms of conjunctivitis. Itch is variable.
Acute pink eye infections typically produce the symptoms of beging very itchy, sometimes distressingly so, and the patient often complains of some lid swelling.
Viral pink eye is often associated with an infection of the upper respiratory tract, a common cold, or a sore throat. Thus, pink eye symptoms include watery discharge, variable itch, and the fact that the infection usually begins with one eye, but may spread easily to the other.
Bacterial pink eye due to the common pyogenic bacteria causes marked grittiness/irritation and a stringy, opaque, grey or yellowish mucoid discharge (gowl is a common regional name) that may cause the lids to stick together, especially after sleeping. However discharge is not an essential symptoms for the diagnosis of pink eye. Many other bacteria (eg, Chlamydia, Moraxella) can cause a non-exudative but very persistent conjunctivitis without much redness. The gritty feeling is sometimes localised enough for patients to insist they must have a foreign body in the eye. The more acute pyogenic infections can be painful. Like viral conjunctivitis, it usually affects only one eye but may spread easily to the other eye.
To assess the symptoms, the patient should be examined in a well lit room. Injection (redness) of the conjunctiva on one or both eyes should be apparent, but may be quite mild. Except in obvious pyogenic or toxic/chemical conjunctivitis, a slit lamp (biomicroscope) is needed to have any confidence in the diagnosis. Examination of the tarsal conjunctiva is usually more diagnostic than the bulbar conjunctiva.
Viral pink eye, shows a fine diffuse pinkness of the conjunctiva which is easily mistaken for the 'ciliary injection' of iritis, but there are usually corroborative signs on biomicroscopy, particularly numerous lymphoid follicles on the tarsal conjunctiva, and sometimes a punctate keratitis.
Pyogenic bacterial pink eye shows an opaque purulent discharge, a very red eye, and on biomicroscopy there are numerous white cells and desquamated epithelial cells seen in the 'tear gutter' along the lid margin. The tarsal conjunctiva is a velvety red and not particularly follicular. Non-pyogenic infections can show just mild injection and be difficult to diagnose. Scarring of the tarsal conjunctiva is occasionally seen in chronic infections, especially in trachoma.
Posted by Staff at June 10, 2005 9:30 PMblog comments powered by Disqus