It is not always possible to detect the cause of a broken blood vessel in the eye, or subconjunctival hemorrhage, but possible causes include vomiting, lifting heavy objects, sneezing and coughing, notes Mayo Clinic. Serious eye infection, rubbing the eye harshly or trauma, such as an eye injury resulting from a foreign object, can also lead to a subconjunctival hemorrhage.
A small blood vessel that bursts beneath the eye's clear surface, called the conjunctiva, is an eye problem known as a subconjunctival hemorrhage, explains Mayo Clinic. Blood from the ruptured blood vessel remains below the surface, as the conjunctiva cannot absorb it rapidly. The condition is often benign, and it typically resolves within one to two weeks. Medical treatment is not necessary in most cases.
Blood-thinning medications, high blood pressure, eye surgeries and viral infections are other potential causes of subconjunctival hemorrhage, states MedlinePlus. The common symptom is a noticeable red patch on the white part of the eye. The appearance of the red patch does not involve any pain, eye discharge or vision changes.
Doctors diagnose the condition by performing a physical exam and checking the affected eye, according to MedlinePlus. They also sometimes check a person's blood pressure and request further tests if the individual shows bleeding or bruising in other body parts. In rare cases, a complete subconjunctival hemorrhage indicates a severe vascular disorder in older people.