What Causes Eye Boogers?

Eye Discharge May Occur Normally Due to Decreased Tear Production

Girl rubbing her eyes in bed
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When morning comes, many people start the day by rubbing their eyes. At the inner edge of each, you may notice the accumulation of a substance that is sometimes called “sleep” or even “eye boogers”. What causes eye boogers? Why don’t they seem to occur as much during the day? Learn about this eye discharge phenomenon and why it is a normal and healthy part of sleep.

A Lesson in Eye Anatomy

The edge of each eye has a fold of skin called the epicanthal fold. Each side of the eye is named differently: the one by the nose is the medial one and the outer one is the lateral one. The medial epicanthal fold covers the medial canthus of the eye. It contains the outlet for drainage canals that connect to a tube (or tear duct) that connects the edge of the eye to the nasal passage. This has important consequences, and helps to explain why debris accumulates with sleep.

Have you ever noticed that your nose starts to run when you are crying? Tears flow from the surface of the eye and collect in the tear duct that passes the fluid into the nose. Though some liquid may flush out the tip of the nose, leading to a drip, other liquid is also cleared down the throat and into the stomach. This is why you may also be able to occasionally taste the salt of your tears with crying.

Tears are made of water, oil, and a protein called mucin. They help to lubricate the surface of the eye and may protect it from infection from viruses and bacteria.

During wakefulness, blinking frequently clears the fluid and debris that comes into contact with the surface of the eye. Imagine the eye’s surface as a rounded window. Each closure of the eyelid simultaneously lubricates and clears any encountered debris from the environment. Dust, pollen, allergens, and any other small particle that you might imagine are swiftly cleansed from the eye. Just like a windshield wiper, the eyelids are cleaning the windows of the eyes.

If significant debris gets into our eyes, it will cause discomfort, redness, and – tearing. Our body is able to flush out particles that have encountered the eye’s surface. Throughout the day, this is accomplished. Proteins and other substances are also cleared away. Occasionally we may even wipe the corners of our eyes to clear this material.

Eye Changes in Sleep

When we are sleep, a few important differences are noted. First, we are not blinking throughout the night. The surface of the eye is kept moist by closed eyes. In fact, conditions that impair eye closure (such as Bell’s Palsy or a stroke) may cause eye dryness. Rarely, people may actually sleep with their eyes partially open. Persistent eye closure changes the dynamics.

Instead of continuous cleansing of the eye’s surface, the proteins (and potentially other debris) are not wiped away. There may also be less tear production, leading to increased dryness. Instead of a continuous cleansing, gravity may aid the material collection at the lower part of the eyes. These materials and some of the fluid created by the eye’s surface are flushed toward the collecting duct, just like a drainpipe. Not all the materials can be easily flushed through, however.

Large volumes or particles of greater size may not be flushed into the nasal passage. When less fluid is present, goop or crud may form more easily. These materials may accumulate in the corner of the eyes. As a result, “sleep” or an “eye booger” may collect and form. In some people, more may accumulate. It may also be affected by abnormal congestion or drainage within the nasal passage, such as with allergies. If the tear duct becomes clogged, problems may develop. Rarely, it can be necessary to open the duct with a supportive tube called a stent.

It is normal to accumulate debris at the corner of the eyes by the nose. In fact, it would be unusual if this never occurred. In addition, the outer epicanthal fold may gather a smaller amount of debris. It may even be noted along the eyelashes.

Most people can clear this debris by simply wiping at the eyes in the morning. If especially tenacious, a warm washcloth can help. Some may find it necessary to clear additional material with the use of saline eye drops. If you develop pain or discharge from your eyes, you should speak with a doctor as this could be a sign of infection or other abnormalities.


Moore, KL and Dalley, AF. "Clinically Oriented Anatomy." Lippincott Williams & Wilkins, 4th edition, 1999, p. 902.

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