The sudden appearance of a bright red spot on the white of the eye is a common experience that often causes immediate alarm. This discoloration is the visible sign of a small blood vessel that has ruptured beneath the eye’s surface. While the appearance can be dramatic, this condition is typically harmless, representing an isolated incident rather than a sign of a serious threat to vision. Exploring the causes of this phenomenon, from simple physical strain to underlying health conditions, helps to demystify the frightening visual symptom.
Identifying the Broken Blood Vessel
The bright red patch seen on the eye is called a subconjunctival hemorrhage. This occurs beneath the conjunctiva, a thin, transparent membrane covering the white part of the eye, known as the sclera. The conjunctiva contains a network of tiny, fragile blood vessels that are susceptible to rupture. When one of these vessels breaks, the blood becomes trapped between the conjunctiva and the sclera, creating the intensely colored spot. This condition is often compared to a bruise on the skin, but because the blood is contained just under a clear layer, the red color appears much more vivid. A subconjunctival hemorrhage is usually painless and does not involve any discharge, swelling, or changes to vision.
Everyday Mechanical Triggers
The most frequent causes of a broken blood vessel in the eye involve a momentary, sharp increase in pressure within the veins of the head and neck. Actions that require forceful expiration against a closed airway, known as the Valsalva maneuver, can generate enough pressure to rupture a delicate capillary. Common examples of this include intense, prolonged coughing fits, violent sneezing, or the physical stress of vomiting.
Other forms of intense straining, such as pushing during a difficult bowel movement or childbirth, can similarly spike venous pressure and trigger a rupture. Even strenuous physical activities like heavy weightlifting can lead to this outcome. Minor trauma to the eye, such as aggressively rubbing the eyes or a direct, slight impact, can also mechanically break the small vessels.
Underlying Systemic and Medication Factors
While many cases are due to isolated physical strain, recurring or spontaneous subconjunctival hemorrhages may point toward an underlying medical issue or the effect of certain medications.
Systemic Conditions
Chronic high blood pressure, or hypertension, is a significant systemic risk factor because it can weaken the walls of blood vessels throughout the body, making them more prone to rupture during a pressure spike. Diabetes can contribute to vascular fragility over time, as it damages small blood vessels throughout the body, including those in the eye. This general weakening can make a person more vulnerable to a subconjunctival hemorrhage, even from minor mechanical forces.
Medications and Clotting
The use of anticoagulant and antiplatelet medications, commonly referred to as blood thinners, dramatically increases the severity of the resulting hemorrhage. Drugs like aspirin, warfarin, or newer direct oral anticoagulants impair the body’s ability to form clots, causing the bleed to be larger and more noticeable. Individuals with blood clotting disorders, such as deficiencies in clotting factors, are also inherently more susceptible to spontaneous or larger bleeds. Recent eye surgery, such as cataract removal, can also be a localized risk factor due to the temporary increase in inflammation and surgical manipulation of the ocular tissues.
When to Seek Professional Care
For most people, a subconjunctival hemorrhage is a benign, self-limiting condition that requires no specific treatment and resolves on its own. The blood is naturally reabsorbed by the body, much like a bruise, typically disappearing completely within one to three weeks. As the blood breaks down, the red patch may change color, often turning a yellowish hue before fading entirely.
It is important to seek immediate professional care if the red patch is accompanied by certain warning signs that suggest a more serious issue. These signs include any pain in the eye, noticeable changes in vision such as blurriness or double vision, or a persistent discharge from the eye. Repeated occurrences of the hemorrhage, especially if they are not linked to a clear physical strain, warrant an evaluation to check for underlying conditions like undiagnosed high blood pressure or a bleeding disorder.