The appearance of whiteness in the inner corner of the eye, known anatomically as the medial canthus, is a common observation. This area contains delicate structures that can sometimes appear lighter than the surrounding tissue. The perception of whiteness stems from three distinct sources: the normal, permanent anatomy of the eye, a temporary buildup of eye discharge, or the development of a chronic tissue growth. Understanding the difference between these possibilities helps to determine if the observation is a natural feature or a sign that medical attention may be necessary.
Understanding the Normal Anatomy
The inner corner of the eye is home to two specialized, healthy structures that are often mistaken for abnormal white or pale growths. These are the lacrimal caruncle and the plica semilunaris, which are permanent and functional parts of the ocular surface. The lacrimal caruncle is the small, fleshy mound of tissue located nearest to the nose.
This tiny mound is composed of skin-like elements, including fine hairs, sweat glands, and oil glands. The oil and mucus it produces are an important contribution to the tear film, helping to stabilize it and keep the eye lubricated. Due to its composition and function, the caruncle naturally varies in color from pale pink or reddish to a slightly whiter or yellowish-white hue.
Adjacent to the caruncle is the plica semilunaris, which translates to “semilunar fold.” This structure is a loose, crescent-shaped fold of the conjunctiva, the clear membrane covering the white of the eye. It is considered a vestigial remnant of the nictitating membrane, or “third eyelid,” found in many other animals.
The plica semilunaris facilitates free movement of the eye toward the nose and helps maintain tear drainage by guiding tears toward the nasal puncta. Because this fold is part of the conjunctiva, it can appear translucent or slightly pale white, especially when the eye is moved. The natural, pale coloring of both the caruncle and the plica semilunaris should not be confused with a disease state.
Transient White Discharge
A temporary white appearance is most frequently caused by eye discharge, commonly referred to as rheum or “sleep crust.” This discharge consists of a mix of mucus, oil, dead skin cells, and debris. Blinking washes this material away during the day, but the lack of blinking while sleeping allows it to accumulate in the medial canthus. Normal rheum is typically white or pale cream, ranging from soft and sticky to dry and crusty.
While a small amount is expected upon waking, excessive or stringy white discharge can suggest an underlying issue. Stringy, white mucus is a common indicator of allergic conjunctivitis, where the immune response produces material that clumps together. A temporary increase in discharge can also be associated with dry eye syndrome, as the eyes may produce a less nourishing form of tears that appear as noticeable, stringy discharge.
Conditions like blepharitis, which is inflammation of the eyelids, can cause abnormal oil production, leading to thick, crusty white discharge along the lashes and inner corner. If the discharge is strictly white or clear, it often points toward irritation, allergies, or a viral cause.
Persistent White Growths and Lesions
In contrast to temporary discharge, a persistent white or yellowish-white spot in the inner corner may indicate a chronic growth on the eye’s surface. The most common is a pinguecula, a non-cancerous, raised bump on the conjunctiva over the white part of the eye, often close to the nose. Its pale color comes from deposits of protein, fat, and calcium. Pingueculae are associated with chronic exposure to environmental irritants, particularly UV radiation, wind, and dust.
Pingueculae are typically harmless and do not affect vision, though they can become inflamed and appear red, a condition known as pingueculitis. The tissue remains confined to the white of the eye and does not grow onto the cornea.
A pterygium is a related condition that starts as a fleshy, wedge-shaped growth, sometimes developing from an existing pinguecula. While a pinguecula is yellowish-white, a pterygium is generally pink or reddish due to visible blood vessels.
While a pinguecula remains confined to the conjunctiva, a pterygium can grow to extend onto the clear cornea. This extension is a serious concern because it can affect the curvature of the cornea, potentially leading to blurry or distorted vision.
When to Consult a Doctor
While many causes of whiteness in the inner eye corner are benign, certain associated symptoms indicate the need for medical consultation.
You should consult a doctor if the white appearance is accompanied by:
- Persistent eye pain or significant sensitivity to light.
- Any sudden change in vision, such as blurriness or distortion.
- Discharge that is thick, sticky, or progresses to a dark yellow or green color.
- Severe redness or swelling around the eye.
- Eyelids that are stuck together upon waking.