Sleep crust is a mixture of mucus, tears, and skin cells that accumulates while you are sleeping. Sometimes it can indicate an infection or other condition.

Person removing eye crust from their eyeShare on Pinterest
Phevos Theodoridis/EyeEm/Getty Images

Picture this: Dawn is breaking and it’s time to wake up. You reach over to quiet your alarm clock, stretch your arms to greet the day, and attempt to open your sleepy eyes… only to find your eyelids are stuck together by a crusty glue-like substance.

Sound familiar?

Sleep crust, also called eye gunk or by its technical name rheum, is pretty common. This mixture of mucus, tears, and skin cells can occur naturally while you’re snoozing.

There’s a spectrum of typical, everyday eye gunk and sleep crust that signals something could be wrong. We’ll fill you in on what this stuff is, why it appears on your eyelids in the morning, and how to take care of it.

Crusty eyes in the morning can include any of the following symptoms:

  • white, cream-colored, or light yellow crust gathered in the corners of your eyelids when you wake up
  • eyelashes stuck to each other with watery or solid discharge from your eyes
  • irritation, redness, and a filmy layer around your eyes when you first open them

Chances are, the sleep crust in your eyes is perfectly natural and part of your body’s self-regulating cleaning system.

Natural causes

During the day, blinking wipes away dust, old cells, extra mucus, and tears from your eyes. While you’re sleeping, you aren’t blinking, but these waste products are still being washed out of your eyes.

Some nights (and for some people, it’s most nights), there might be enough to create a crusty film on the corner of your eyelids. If you have allergies, you may notice extra eye crust during certain times of the year. This still falls within the realm of a natural cause.

Blepharitis

Blepharitis is the technical term for eyelid inflammation. Blepharitis has several possible causes, but one of the symptoms can be extra crusty discharge from your eyes during the night.

Some signs that you may have blepharitis can include:

  • eye redness, irritation, or itchiness
  • eyelids that stick together
  • skin flakes at the base of your eyelid
  • foamy tears
  • burning or stinging eyes
  • sensitivity to light
  • watery or dry eyes

Blepharitis typically occurs in both eyes and rarely affects one eye at a time.

Conjunctivitis

Conjunctivitis (pink eye) is any inflammation that impacts your conjunctiva, which is a thin membrane that lines part of your eye.

Conjunctivitis can be bacterial or viral. It can also be related to allergies or environmental factors.

If you have pink eye, you may notice symptoms like:

  • eye redness
  • extra crust gathering in the corner of your eye
  • watery discharge that may build up in your eye
  • a gritty feeling between your eyelids due to water buildup

Conjunctivitis can be in one eye, or it can affect both.

Eye stye

A stye is an infection of the eye that causes a pustule to form on the upper or lower eyelid. This results from infected or inflamed oil glands or follicles in your eyelid.

A stye can be painful and cause yellow mucus to build up in the corners of your eye.

If you have a stye, you’ll typically notice that only one of your eyes is getting extra crusty.

Blocked tear duct

A blocked tear duct stops your eyes from draining normally. If you have this condition, you may notice small balls of yellow or white mucus gathering around the corner of one of your eyes.

Other symptoms affecting your eyelid may include:

  • redness
  • irritation
  • pain
  • swelling

Dry eye

When you have chronic (or even occasional) dry eye, your eye may produce stringy mucus. This can result in an accumulation of eye crust that’s gritty or sticky.

If eye crust is your only symptom, you can probably treat it at home.

The American Academy of Ophthalmology emphasizes washing your hands before you try to rub any morning goop out of your eyes. It can be hard to resist the impulse to wipe the crust from your eyes, but your hands often carry bacteria and germs.

Instead of using your bare (dirty) hands, try a clean washcloth with warm water on it. Apply the washcloth to your eyes gently, and most eye crust will dissolve.

You might need to leave the washcloth on for a few minutes to completely clear your eye.

If your eyes feel gritty or dry after wiping out the crust, you may want to use eye drops to hydrate your eyeballs and prepare for the day. Hydrating eye drops or saline solution are available over the counter and can help cleanse your eye of any remaining film or gunk.

Some symptoms indicate that it’s time to go beyond home remedies and see an eye doctor. These symptoms can include:

  • any pain in your eye
  • redness and irritation in your eye
  • difficulty opening your eye, due to eye gunk or otherwise
  • green or dark yellow eye discharge
  • light sensitivity
  • blurred vision

An eye doctor can do an initial exam to determine the cause of your symptoms. They may prescribe prescription eye drops or antibiotics to address any infection or inflammation. This may include blepharitis or conjunctivitis.

Chronic dry eye may also be treated with eye drops.

If you take good care of your eyes, you may find less eye gunk greeting you when you wake up. Here are some eyelid hygiene tips:

Eyelid hygiene tips

  • Always wash your face before bed and gently cleanse your eye area with a clean, cool washcloth. (Avoid using soap or cleanser in the eye area.)
  • Remove eye makeup thoroughly before you head to bed. Consider using an eye makeup remover, a cotton pad, or a makeup removal wipe for the area around your eyes.
  • Avoid touching and rubbing your eyes as much as possible throughout the day. Wash your hands if you do have to touch your eyes.
  • Remove your contact lenses before you lie down. It’s also best to avoid extending the life of your contacts beyond what the manufacturer recommends.

If you’re waking up with sleep crust in your eyes, it’s most likely the result of your eyes doing their perfectly natural and healthy daily cleansing ritual.

However, if you’re accumulating a lot of crust specifically in one eye, if you notice that your eye crust is a strange color, or if you have symptoms of itching or redness, another health condition may be at play.

Your eyes are highly complex and sensitive, so if you’re concerned about your eye health, speak with a doctor immediately.