Eye crust, also known as rheum or sleep crust, is a natural accumulation of mucus, oils, dead skin cells, and dust that gathers in the corners of your eyes, particularly after sleep. This discharge serves a protective function, working to clear away waste products and potentially irritating debris from the tear film and the front surface of the eye. While a small amount of eye crust in the morning is a typical part of ocular health, an excessive or unusual amount can sometimes indicate an underlying condition.
The Normal Process
Throughout the day, your eyes are constantly producing tears and mucus, which form a protective tear film across the ocular surface. The act of blinking continuously washes away this natural discharge, preventing its accumulation and flushing debris through the tear ducts. This continuous cleansing mechanism helps maintain clear vision and eye comfort.
During sleep, however, blinking ceases, and the eyes remain closed. With the absence of blinking, the eye’s natural secretions—composed of mucin from the conjunctiva and oily meibum from the meibomian glands—along with trapped dust and shed skin cells, begin to collect. This accumulated material gathers in the inner corners of the eyes and along the lash line, where the liquid component can evaporate, leaving behind the sticky or crusty residue.
Common Causes of Excessive Eye Crust
An increased amount of eye crust, or changes in its consistency or color, can point to various eye conditions. These conditions often lead to excessive discharge as the eye attempts to clear itself of irritants or infections.
Conjunctivitis (Pink Eye)
Conjunctivitis, an inflammation of the conjunctiva, frequently causes excessive eye discharge. Bacterial conjunctivitis often results in a thick, sticky discharge that can be yellow, green, or gray, sometimes causing eyelids to stick together upon waking. In contrast, viral conjunctivitis produces a clear, watery discharge, though it may include a white or light yellow mucus component. Both forms are highly contagious.
Allergies
Allergic reactions can also lead to increased eye crust, characterized by watery or stringy discharge. When allergens like pollen, dust, or pet dander contact the eye, mast cells in the conjunctiva release histamine. This release triggers an immune response, causing blood vessels in the conjunctiva to swell and leading to symptoms such as intense itching, redness, and excessive tearing, which contributes to the discharge.
Dry Eye Syndrome
Dry eye syndrome can sometimes manifest with excessive tearing and discharge. This occurs because the tear film, which normally lubricates the eye, becomes unstable or deficient in its water or oil components, leading to irritation. The eye responds to this irritation by producing reflex tears, which are often watery and lack the proper balance of oils and mucus needed for effective lubrication, resulting in stringy or sticky discharge.
Blepharitis
Blepharitis is an inflammation of the eyelids that leads to crusty debris and discharge. This condition is frequently linked to bacterial overgrowth or dysfunction of the meibomian glands, which produce oils for the tear film. The inflammation can cause redness, swelling, itching, and flaking of skin on the eyelids, contributing to the accumulation of oily or flaky crusts along the lash line.
Blocked Tear Ducts
A blocked tear duct prevents tears from draining properly. Tears, along with mucus and other debris, accumulate in the eye, leading to watery eyes and a sticky discharge. This blockage can occur due to infection, injury, or an underdeveloped duct. The stagnant tears and mucus can also become infected, increasing discharge.
When to Seek Medical Advice
Certain accompanying symptoms suggest that medical evaluation is needed. If you experience significant eye pain, increased redness, or noticeable swelling around the eye, seek medical advice. Blurred vision or increased sensitivity to light are also concerning signs.
Discharge that is thick, yellow, or green, or that is present in large amounts, indicates a bacterial infection. If the crusting is so severe that it prevents your eyes from opening in the morning, or if you have a foreign body sensation that persists, consult a doctor. Additionally, if eye symptoms are accompanied by a fever or other signs of systemic illness, seek medical advice.
Daily Eye Care Tips
Maintaining good eye hygiene can help manage minor eye crust and promote overall eye health. Gently cleaning the eye area with a warm compress can help loosen and remove accumulated crust. Soak a clean washcloth in warm water, wring it out, and place it over your closed eyes for a few minutes to soften the discharge before gently wiping it away.
Wash your hands with soap and water before touching your eyes or eyelids. Avoid rubbing or scratching your eyes, as this can worsen irritation or spread infections. To prevent cross-contamination, avoid sharing personal items like towels, washcloths, or eye makeup. If you wear contact lenses, adhere to proper cleaning and replacement schedules, and remove them before sleeping to reduce irritation and discharge. Staying hydrated also supports healthy tear production.