The sudden appearance of a bright red spot on the white part of your eye can be an alarming sight, often prompting immediate concern. This visible patch of redness is typically a collection of leaked blood situated just beneath the transparent membrane that covers the eye, known as the conjunctiva. While the dramatic appearance might suggest a serious injury, a localized red spot is most frequently a benign event that looks worse than it actually is.
Subconjunctival Hemorrhage: Definition and Appearance
The condition most commonly responsible for a red spot is a subconjunctival hemorrhage, which occurs when a tiny blood vessel breaks just under the conjunctiva. This clear, thin tissue covers the sclera, or the white part of the eye, and is filled with numerous small, fragile blood vessels. When one of these capillaries ruptures, the blood becomes trapped between the conjunctiva and the sclera, creating a starkly demarcated red patch.
The defining visual characteristic of a subconjunctival hemorrhage is its bright red color and its flat appearance, often resembling a splash of red paint on the eye’s surface. Unlike other forms of eye redness, this specific type of bleeding is generally painless and does not cause vision changes, discharge, or light sensitivity.
Because the blood is confined to the surface layers, it is reabsorbed by the body over time, similar to a bruise healing on the skin. The spot will typically start out a vibrant red and may progress to a darker red, then a yellowish-green hue before disappearing completely. Most of these hemorrhages resolve entirely on their own, requiring no specific medical treatment, typically within one to three weeks.
Common Triggers for Eye Redness
A subconjunctival hemorrhage is often caused by a sudden, transient increase in pressure within the veins of the head and neck, which can overwhelm the delicate walls of the conjunctival blood vessels, causing them to rupture. This mechanism is frequently triggered by what are known as Valsalva maneuvers, involving forceful exhalation against a closed airway.
Common actions that create this pressure include severe episodes of coughing, sneezing, or forceful vomiting. Other straining activities, such as heavy lifting, intense exercise, or bearing down during a difficult bowel movement, can also lead to a burst vessel. Even something as simple as rubbing the eye too vigorously or experiencing minor trauma to the eye area can be enough to cause the bleed.
Certain underlying health factors can increase the likelihood of these spots occurring, making the blood vessels more fragile. Conditions like high blood pressure or diabetes are associated with an increased risk of vessel fragility. Additionally, people taking blood-thinning medications, such as aspirin or warfarin, may be more prone to developing a subconjunctival hemorrhage.
Differentiating Other Red Spots
While a subconjunctival hemorrhage is the most common cause of a localized red spot, other conditions can also cause redness or growths on the eye’s surface. A pinguecula is a yellowish, raised spot on the conjunctiva, typically located closer to the nose. This benign growth is composed of protein, fat, or calcium deposits, though it can become inflamed and appear red when irritated.
Another growth that can cause localized redness is a pterygium, which is a fleshy, triangular-shaped tissue growth that begins on the conjunctiva. Unlike a pinguecula, a pterygium is characterized by its ability to spread onto the clear dome of the eye, the cornea. If it continues to grow across the cornea toward the center of the eye, it can potentially affect vision and may require surgical removal.
Less common causes of localized redness include inflammatory conditions like episcleritis, which involves inflammation of the tissue layer beneath the conjunctiva. Episcleritis presents as a localized area of redness, often with mild irritation, but it lacks the distinct, uniform appearance of a hemorrhage. The vessels are often more congested and can be distinguished by their response to certain eye drops, unlike a subconjunctival hemorrhage.
Warning Signs Requiring Immediate Care
Although most red spots are harmless, certain accompanying symptoms suggest a more serious underlying issue that requires immediate medical evaluation. Pain is a significant indicator, especially if it is severe, throbbing, or accompanied by a headache, as an uncomplicated hemorrhage should not be painful. Any sudden change in vision, such as blurriness, double vision, or a decrease in visual acuity, is also a serious warning sign.
Other symptoms that warrant an urgent visit to an eye doctor include:
- The presence of discharge, particularly if it is thick or purulent, or if the eye is unusually sensitive to light.
- If the red spot resulted from a significant injury to the eye or head, or if there is swelling around the eye, requiring prompt care to rule out deeper damage.
- If the redness does not begin to fade within two weeks.
- If the red spots occur repeatedly without a clear cause, requiring examination for underlying conditions like uncontrolled high blood pressure or a bleeding disorder.