You have been diagnosed as having a sub-conjunctival haemorrhage, sometimes known as a 'sub-conj haemorrhage' for short.
 

What it is

The front, white part of the eye, known as the sclera, is covered by a transparent membrane called the conjunctiva.  The conjunctiva has a rich blood supply.  A sub-conjunctival haemorrhage occurs when these tiny blood vessels leak, causing a small amount of blood to gather between the sclera and conjunctiva.  Because these membranes are transparent this condition looks very serious, but it is not.  It will not interfere with your sight.  This is the same process which causes bruising, which is a small bleed in between the layers of the skin.
 

Symptoms

The eye will look very bloodshot and you may have a feeling of ‘tightness’ in the affected eye.
 

Causes

• Coughing, knocking your eye, or rubbing it extremely hard. 
• Diabetes or high blood pressure . 
• Aspirin or warfarin. 

Practically all sub-conjunctival haemorrhages occur for no reason.  In most cases it does not mean you have an illness or eye condition.
 

 Treatment

• Apart from an eye examination, we will also check your blood pressure and give you a routine test for diabetes. 
• It does not require treatment. 
• The bloodshot appearance should go in 7 to 14 days.