The exact term for what is commonly known as "eye wax" or "sleep crust" is rheum.
What Exactly is Rheum?
Rheum (pronounced /ruːm/) is a thin, natural mucus discharged from the eyes, often accumulating during sleep. Its name originates from the Greek word ῥεῦμα (rheuma), meaning 'a flowing' or 'rheum'. This substance is distinct from mucopurulent discharge, which indicates an infection.
While you sleep, your eyes are closed, preventing tears from washing away debris. This allows rheum to dry and gather as a crust, typically found in the corners of the eyes, on the eyelids, or sometimes even around the mouth or under the nose. It's a normal and healthy bodily function, serving as part of your eyes' natural cleaning process.
Common Names for Eye Wax
Beyond its technical name, rheum is widely known by several more informal terms:
- Sleep crust
- Sleep dust
- Eye gunk
- Eye boogers
- Goop
- Sand in the eyes
The Science Behind Eye Wax Formation
Composition
Eye rheum is primarily composed of:
- Mucus: Produced by the conjunctiva, the clear membrane covering the white part of your eye and lining the inside of your eyelids.
- Oils: Secreted by the meibomian glands located on the edges of your eyelids. These oils help lubricate the eye and prevent tears from evaporating too quickly.
- Dead skin cells: Naturally shed from the eyelids and surrounding areas.
- Dust and environmental debris: Tiny particles that enter the eye throughout the day.
- Tears: The fluid that helps wash away foreign substances.
Function
The primary function of rheum is to act as a protective mechanism. As you blink during the day, tears continuously wash away these components. However, when you sleep, blinking stops, allowing these substances to accumulate and dry, forming the characteristic crust. This process helps to:
- Clear debris: It traps and removes irritants, dust, and microorganisms from the eye's surface.
- Maintain eye health: By preventing foreign particles from remaining in contact with the delicate eye tissues for extended periods.
When Eye Wax Might Be a Concern
While a small amount of clear or whitish rheum is normal, changes in its quantity, color, or consistency can indicate an underlying issue.
Normal vs. Abnormal Eye Discharge
| Characteristic | Normal Eye Rheum | Abnormal Eye Discharge |
|---|---|---|
| Color | Clear, whitish, light yellow | Green, dark yellow, brown, gray |
| Consistency | Thin, slightly sticky, dries to a crust | Thick, pus-like, watery, stringy |
| Amount | Small, manageable, mostly after sleep | Excessive, constant throughout the day, causes blurring |
| Associated Symptoms | None, slight dryness upon waking | Redness, pain, itching, burning, swelling, light sensitivity, blurry vision |
| Potential Causes | Natural bodily function | Infection (bacterial, viral), allergy, dry eye syndrome, injury, foreign body |
Signs to Watch For
If you notice any of the following, it's advisable to consult an eye care professional:
- Increased volume: Significantly more discharge than usual.
- Changes in color: Green, yellow, or gray discharge can signal a bacterial infection like conjunctivitis.
- Thick, pus-like consistency: Indicative of an infection.
- Eye discomfort: Persistent redness, itching, burning, pain, or swelling.
- Crusting that glues eyelids shut: Especially in the morning.
- Blurred vision: Due to excessive discharge.
- Sensitivity to light (photophobia).
Conditions like bacterial conjunctivitis, viral conjunctivitis, allergic conjunctivitis, dry eye syndrome, or even a blocked tear duct can lead to abnormal eye discharge.
Proper Eye Hygiene for Managing Eye Wax
Maintaining good eye hygiene is key to managing normal eye rheum and preventing potential issues.
- Gentle Cleaning: Use a clean, warm, damp cloth or cotton ball to gently wipe away rheum from the corners of your eyes and eyelids. Always wipe from the inner corner outwards.
- Avoid Rubbing: Do not rub your eyes with your fingers, as this can introduce bacteria and worsen irritation.
- Separate Cloths: Use a fresh part of the cloth or a new cotton ball for each eye to prevent cross-contamination if one eye is irritated.
- Hand Washing: Always wash your hands thoroughly with soap and water before and after touching your eyes.
- Contact Lens Care: If you wear contact lenses, ensure you follow all proper cleaning and storage guidelines. Never sleep in lenses unless specifically approved by your eye doctor. For more information, refer to guidelines from the American Optometric Association.
- Makeup Removal: Always remove eye makeup before sleeping to prevent irritation and blockages of the meibomian glands.
By understanding what rheum is and how to properly care for your eyes, you can maintain optimal eye health.
