Waking up with a small amount of “sleep” or “sand” in the corner of your eyes is a near-universal human experience. This morning residue is simply a natural byproduct of your eyes’ continuous self-cleaning process. It accumulates overnight and is typically harmless, presenting as a pale, dry crust or a slightly sticky film. This common occurrence is a normal function of a healthy tear film.
What is Ocular Rheum
The technical term for this eye crust is ocular rheum, and it is a complex mixture of materials your eye naturally produces and sheds. The core components include mucus, which is produced by the conjunctiva to trap debris, and oil, which comes from the meibomian glands along the eyelid margins. Rheum also incorporates dead skin cells that have exfoliated from the eyelid and face, as well as environmental dust particles. It is essentially the debris that the eye has collected and flushed out of the tear film.
Why Crust Accumulates During Sleep
The buildup of rheum into a noticeable crust is directly linked to the cessation of blinking during sleep. While you are awake, each blink acts like a windshield wiper. This action spreads the tear film evenly across the eye and actively sweeps the collected mucus, oil, and debris toward the tear ducts near the nose for drainage. Once you are asleep, blinking stops entirely, removing the flushing action that clears the eye’s surface. Tear production also slows down significantly overnight, allowing the mixture of mucus and oils to dry out and harden, accumulating in the inner corner of the eye or along the lash line.
When to Consult a Doctor About Eye Discharge
While a small, dry, and light-colored morning crust is normal, certain changes in eye discharge can signal a need for medical attention. If the discharge becomes excessive, sticky enough to seal your eyelids shut, or changes color, it may indicate a pathological condition. Discharge that is thick, yellow, or green often suggests a bacterial infection, such as bacterial conjunctivitis, which requires treatment. Other warning signs include discharge accompanied by persistent pain, increased eye redness, blurred vision, or extreme sensitivity to light. If you experience any of these symptoms, or if the discharge continues throughout the day, consult an eye care professional for an accurate diagnosis. Conditions like blepharitis or a blocked tear duct can also cause abnormal crusting and may need specific management.
Safe Eye Cleaning and Prevention
Removing the morning crust safely involves gentle methods to avoid irritating the delicate skin around the eyes. Always wash your hands thoroughly before touching your eyes to prevent the introduction of bacteria. The most effective way to loosen a dry, crusty buildup is by applying a clean washcloth soaked in warm water to your closed eyes for a few minutes. After softening the rheum, gently wipe the area clean, moving from the inner corner of the eye outward. Use a fresh section of the cloth or a new cotton ball for each eye to prevent potential cross-contamination. To minimize future buildup, focus on good daily hygiene, such as removing all eye makeup before bed and changing your pillowcases frequently.