After you fire up the barbecue grill, the charcoal briquettes you use as fuel are eventually reduced to a pile of charred remains and ashes. This residue contains recycled plant material and naturally occurring minerals, but it may also contain harmful chemicals.
Burst blood vessel in the eye. Straining, coughing or injuring your eye can sometimes cause a blood vessel to burst on the eye surface, causing a bright red blotch. This is called a subconjunctival haemorrhage.
Injury. If a small particle or foreign object becomes lodged on the eye or under the eyelid, the object may scratch the white of the eye, causing a broken blood vessel. Playing baseball, or other sports where a ball or object may hit the eye, may also cause the condition.