A vigorous cough can sometimes lead to a bright red spot on the white of your eye. While visually dramatic, this phenomenon is typically benign. Understanding its cause can alleviate concerns.
How Coughing Affects Eye Blood Vessels
A forceful cough creates a sudden increase in pressure within the chest and abdomen. This action, similar to a Valsalva maneuver, temporarily impedes blood flow from the head and neck back to the heart. As this pressure builds, it can extend to the delicate blood vessels in the eyes.
The conjunctiva, a thin membrane covering the white of the eye, contains tiny, fragile capillaries. The sudden spike in venous pressure from coughing can cause these superficial capillaries to rupture. This leakage of blood is typically minor, but it becomes highly visible against the white background of the sclera.
What the Red Spot Means
The red spot is medically known as a subconjunctival hemorrhage. This condition is essentially a bruise on the eye, where blood has leaked from a broken vessel and become trapped beneath the conjunctiva. Despite its bright red appearance, a subconjunctival hemorrhage is generally harmless and does not cause pain or affect vision.
The blood spot can range in size from a small dot to a larger area covering much of the white of the eye. It typically resolves on its own without treatment, much like a bruise on the skin. The body naturally reabsorbs the blood, and the spot usually fades within one to two weeks, sometimes changing color to yellow as it heals.
When to Be Concerned
While subconjunctival hemorrhages are usually not serious, certain symptoms or recurring instances warrant medical evaluation. Seek professional medical attention if the redness is accompanied by eye pain, changes in vision (e.g., blurriness or loss of sight), or any discharge from the eye. Sensitivity to light or a persistent feeling of something in the eye are also reasons for concern.
Consult a healthcare provider if a red eye appears frequently without significant coughing or straining, or with other symptoms like headache, dizziness, or fever. Those on blood-thinning medications or with bleeding disorders should consult a doctor, as recurrent or large hemorrhages may signal an underlying systemic issue. Any red eye after direct eye trauma requires immediate medical attention.