When people search for what it means if their “eyes are pearl,” they are usually referring to the appearance of an unusually bright, clear, or vivid white sclera. The sclera is the dense, protective outer layer that covers the majority of the eyeball. Its appearance can provide clues about a person’s general health. A “pearly” sheen is a subjective description that generally points to an extremely white, vivid sclera that stands out against the surrounding facial tissue.
Visual Characteristics of the Sclera
The sclera is primarily composed of tough, interwoven collagen fibers, which are responsible for its naturally opaque, white appearance. This connective tissue layer is relatively thin, ranging from 0.3 to 1.0 millimeters in thickness. Its random fiber arrangement prevents light from passing through, giving it the characteristic white hue. A “pearly white” sclera describes heightened brightness and clarity, often suggesting a youthful or healthy look. This extreme whiteness is perceived when the overlying conjunctiva, the thin, clear membrane covering the sclera, is highly transparent and free from irritation.
The vividness of the sclera is perceived in contrast to the surrounding skin and the colorful iris. When the sclera is exceptionally clear, it can reflect light with a slight shine, which may be interpreted as a pearly or opalescent quality. In infants, the sclera is naturally thinner, sometimes allowing the dark, underlying choroid tissue to show through slightly, giving the eyes a faint bluish tint. As a person ages, the sclera can naturally accumulate small, yellowish or reddish deposits, which makes a super-white appearance less common.
Underlying Causes for Scleral Appearance Changes
The appearance of the sclera is influenced by genetics, environmental factors, and internal physiological processes. Some individuals are genetically predisposed to having a naturally brighter, whiter sclera due to the density and organization of their collagen fibers. Hydration status also plays a role, as good hydration helps maintain the clarity and health of the conjunctiva, making the underlying sclera appear clearer and brighter.
An unusually pale or white sclera may be a subtle sign of an underlying medical condition, such as anemia or iron deficiency. These conditions are characterized by a reduced number of red blood cells or lower hemoglobin levels. This decreases blood flow and pigmentation in the small vessels covering the sclera. This lack of color can make the sclera appear noticeably whiter, or even slightly bluish due to thinning tissue. Poor sleep or fatigue can also make the surrounding skin appear darker, creating a stronger contrast that emphasizes the white of the eyes.
The sclera’s appearance can shift to other colors, representing a change in the body’s chemistry. The opposite of a pearly white sclera is a yellowish discoloration, known as scleral icterus, which is a symptom of jaundice. This yellowing is caused by a buildup of bilirubin, a byproduct of broken-down red blood cells that the liver normally filters out. A reddish hue points to dilated blood vessels in the conjunctiva, often due to irritation, allergies, or an infection like conjunctivitis.
Accompanying Symptoms That Require Medical Evaluation
While a bright, white sclera is often perceived as a sign of health, any sudden or noticeable change in the eye’s appearance warrants medical attention, especially when accompanied by other symptoms. Persistent yellowing (icterus) should be evaluated immediately by a healthcare provider, as it may indicate dysfunction in the liver, gallbladder, or pancreas. If the sclera exhibits a persistent blue or grey tint, particularly in children, it may suggest thinning connective tissue associated with rare conditions like osteogenesis imperfecta or Marfan’s syndrome.
Any paleness or excessive whiteness accompanied by chronic fatigue, weakness, or shortness of breath should prompt a visit to rule out conditions like anemia or iron deficiency. Other red flag symptoms include pain, blurred vision, discharge, or sensitivity to light, regardless of the scleral color. Localized growths or spots, such as a yellowish bump called a pinguecula or a wedge-shaped growth called a pterygium, should also be checked by an eye care professional to monitor their size.