Pink (Red) Eye

Pink or red eye is a term used to describe inflammation of the conjunctiva and the medical description of this in one word is ‘conjunctivitis’. The term conjunctivitis is a word used to describe any inflammation of the conjunctiva and does not necessarily mean that there is an infection present. Most cases of red or pink eye are not contagious. The conjunctiva is the epithelial protective covering of the white of the eye and also covers the inside surfaces of the eyelids.

The causes of pink eye are many and varied. The red or pink colour is due to the dilation of blood vessels within the conjunctiva. Blood vessels dilate in a response to assaults of various kinds. For instance if the eye becomes dry it will appear as a pink eye. An example of this would be a child who plays computer games and will not blink in case he loses the game. After a while due to lack of lubrication the eye will react by becoming red in colour. The cornea is the front transparent surface of the eye and if it becomes dry it will be affected by dry spots which in turn cause redness. Any infection of the cornea or conjunctiva will cause redness.

Typical causes of conjunctivitis include

The relatively common condition called adenoviral conjunctivitis that cause bilateral pink or red eye. The red eye caused by this virus can be quite dramatic looking and the eyes can be quite irritated, watery and sticky. It is highly contagious and can sometimes be associated with a cold or flu-like symptoms. This condition spreads rapidly through class rooms and often teachers suffer from this condition as well as other people who care for children. The treatment for this condition is “supportive” as antibiotics will not help so lubricants and cool compresses can help the symptoms, usually the condition resolves within a week or two but occasionaly this condition can still cause pink or red eye for months after the infectious stage.

Sometimes bacterial infection form a cold or sinusitis or from contact with another person with bacterial conjunctivitis can be the cause of a red eye. In addition to red or pink eye, bacterial conjunctivitis can also be associated with a sticky mucus, or even yellow pus, which has often to be wiped off in the mornings (Picture 1). These cases should be treated with antibiotic eye drops that your doctor will prescribe.

Bacterial conjunctivitis associated with sticky mucus, or even yellow pus

Picture 1: Bacterial conjunctivitis associated with sticky mucus, or even yellow pus

Sore red eyes from over-wearing your contact lenses, such as sleeping in them, can be a cause for concern. If you have a red eye from this cause the contact lens should be immediately removed and medical help should be sought if the condition doesn’t settle within a few hours.

‘Dry eyes’ is a very common cause of pink eye due to inadequate tear production and lubricant eye drops can be very useful in treating this condition. If you suffer from persistent dry eyes then you should visit your doctor who will refer you on to an ophthalmologist (eye doctor) if this is indicated.

Dry eyes are often associated with the skin condition rosacea. This condition is very common in Irish people and red or pink eye is often the result (Picture 2). In this photo you can see not only the red eye but also the red skin ‘rosacea’.

Red or pink eye with rosacea skin condition

Picture 2: Red or pink eye with rosacea skin condition


  • If the eye is pink or red and associated with pain then it is essential that you seek medical help
  • If you have a red or pink eye associated with contact lens wear then medical help should be sought immediately
  • A more serious condition causing red or pink is iritis or uveitis. This condition is associated with deep pain in the eye and an eye doctor should be consulted
  • A foreign body in the eye will cause irritation as well as pink or red eye and this needs to be diagnosed and treated by your own doctor or an eye doctor