A white appearance in the eye can signal various underlying conditions. While the sclera, the white outer layer of the eye, is naturally white, any new or unexpected white discoloration in other parts of the eye may indicate a health issue. This abnormal white appearance can manifest in different areas of the eye, each potentially indicating a distinct concern.
The Healthy Eye
A healthy eye presents a clear and bright appearance. The sclera, the white part of the eye, should be uniformly white without any redness or yellow discoloration. The cornea, the transparent outer layer covering the front of the eye, is clear and allows light to pass through. Behind the cornea, the iris is the colored part of the eye, and at its center is the pupil, which appears black.
White Appearance in the Pupil
When the pupil appears white, gray, silvery, or yellow instead of its typical black, it is medically termed leukocoria, meaning “white pupil.” This abnormal reflection indicates that light is bouncing off something other than the retina. Leukocoria can be a symptom of serious eye conditions, particularly in children.
One common cause of leukocoria is cataracts, which involve a clouding of the eye’s natural lens. These cloudy areas can appear white or milky-white behind the pupil, hindering light from reaching the retina. While common in older adults, cataracts can also be present at birth (congenital) or develop in children. In children, leukocoria can also be a sign of retinoblastoma, a rare type of eye cancer. Other conditions that can cause a white pupillary reflex include Coats’ disease, where abnormal blood vessels grow in the eye, and toxocariasis, an infection caused by a parasitic worm. Any observation of a white pupil warrants immediate evaluation by an eye care professional, especially in children.
White Appearance on the Cornea
A white or cloudy appearance on the cornea, the clear dome at the front of the eye, can stem from several conditions.
Corneal Scars
Corneal scars, often resulting from injury or infection, can leave opaque areas on this transparent surface. These scars can interfere with vision.
Corneal Ulcers
Corneal ulcers, which are open sores on the cornea, typically appear as a gray or white spot or patch. These ulcers can cause pain, redness, blurred vision, and sensitivity to light. They are often caused by infections, including bacterial, viral, or fungal agents, and are more common in contact lens wearers.
Corneal Dystrophies
Corneal dystrophies, a group of genetic conditions, can lead to clouding of the cornea with various patterns of white or grayish-white deposits. These can manifest as lines, circles, or crystalline appearances, sometimes affecting vision progressively.
Arcus Senilis
Arcus senilis presents as a white, gray, or blue ring around the outer edge of the cornea. This ring is composed of fatty deposits and is a common, harmless sign of aging, though its appearance in younger individuals may warrant a check for high cholesterol.
White Appearance on the Sclera
The sclera, the white part of the eye, can also develop abnormal white appearances on its surface.
Pinguecula
A pinguecula is a yellowish-white, raised growth on the conjunctiva, the clear membrane covering the sclera. These growths are often located on the side of the eye closer to the nose and are typically harmless. They are thought to be caused by chronic exposure to sunlight, wind, and dust.
Pterygium
A pterygium is a fleshy, wedge-shaped growth that also originates on the conjunctiva but can extend onto the cornea. It may appear whitish or pinkish and often has visible blood vessels. Like pinguecula, pterygia are linked to prolonged exposure to UV light and environmental irritants. While often benign, a pterygium can affect vision if it grows large enough to cover the pupil or alters the shape of the cornea.
When to Seek Professional Medical Advice
Observing any unusual white appearance in the eye warrants a consultation with an eye care professional, such as an optometrist or ophthalmologist. Timely professional evaluation is important for proper diagnosis and treatment. This is particularly true if the white appearance is accompanied by sudden onset, pain, or changes in vision.
Immediate medical attention is also advised if a white appearance is noticed in a child’s eye, as this can be a sign of serious conditions. Self-diagnosis is not appropriate, and a thorough examination by an eye specialist can determine the underlying cause and guide necessary interventions to protect eye health and preserve vision.