The crust in our eyes is called rheum or “sleep” when we awaken. The British use the word gound to describe it. Other terms are eye boogers, Sandman’s sand, eye goop, eye gunk, or my favorite — sleepy dirt. Nevertheless, the substance consists of mucus, blood cells, skin cells, and dust that blend with meibum, a clear fluid naturally produced in the eyes.
Crusty eyes are a result of a collection of fluids, mucus, blood, skin cells, and dust.
Crusty eyes are typically normal, but they also may be a sign of other eye conditions or eye infections.
Treatment for crusty eyes is conservative, including warm or cold compresses and good handwashing techniques.
In some instances, crusty eyes must be treated by treating the underlying cause first.
Most of the time, crusty eyes are nothing to worry about, but there are exceptions.
Waking with clumps of crusty stuff in the corners of our eyes is normal. We don't continually clean our eyes when asleep because we aren't blinking. As a result, dirt, dust, skin cells, mucus, and tear fluid accumulates. Then, when we wake after a good long, restful snooze, that stuff that has gathered in the corner of our eyes has dried out.
How does eye crust form?
Our cornea is an essential part of our eyes for vision. When we blink, we produce normal mucus by the conjunctiva, a thin mucous membrane that lines the inside of the eyelids, and oil from the meibomian glands, which line the eyelids near the eyelashes. The oil from the meibomian glands, or meibum, forms the outer layer of our tears. Meibum helps prevent our tears from evaporating.
Since we don’t normally blink when we sleep, the tears collect mucus, blood cells, skin cells, and dust to form crust. The crust collects at the corners of our eyes, which are called the canthus. We have a medial (toward our nose) and a lateral (toward the side of our head) canthus in each eye, where the crust usually forms. The reason the eye crust collects more medially is that that is where our tears drain into our nose and nasal cavity through a conduit or pathway called the nasolacrimal duct.
If the nasolacrimal duct becomes blocked, it can cause excessive tearing called epiphora. If someone has excess tears, like when they are crying or have watery eyes, the nasolacrimal duct is the reason we can taste our salty tears. Eye crust can form because the nasolacrimal duct is not working properly in some patients.
We don’t blink when we sleep, so eye discharge tends to collect in the canthus regions as well as along the eyelash line. Normally, the eye discharge can become hard, crusty, sticky, and even change colors to yellow or green.
When are crusty eyes a problem?
Chances are, the crusty eyes that you wake up with from time to time are normal, even if the crust is discolored. All of us experience eye crusting at times, especially if we are experiencing dry eyes, allergies, cold symptoms, or other respiratory ailments.
This leads to the potential reasons why crusty eyes may be a sign of something else. There are many signals that you should look out for, include:
- Light sensitivity
- Blurry vision or loss of vision
- Scratchy eye or pain
- Redness or swelling either around or in the eye
- Trouble opening your eyes because of the stickiness of the crusting
- Eye discharge, especially if it is discolored or white or has a foul odor
One issue to be concerned about is possible dry eye syndrome, which can occur even in healthy people. Dry eyes can occur with hormonal changes when your eyes produce fewer tears. In addition, one possible dry eye condition to be aware of is meibomianitis, which represents inflammation of the meibomian glands.
Dry eyes can cause eye crusting from other causes, too, such as:
- Sun exposure
- Dry work environments
- Some cold and allergy medicines like antihistamines
- Contact lens usage
- Prior to eye surgery
- Heat or chemicals
- Some prescription eye drops that are prescribed for other reasons
Another possible reason for crusty eyes is blepharitis, which causes red, itchy eyes or eyelids — inflammation of the eyelids. It can cause flakes or oil particles and become wrapped around the eyelids. Many people with oily skin or dandruff can suffer from blepharitis.
Blepharitis can be treated with warm compresses, eyelid scrubs, antibiotic ointment, artificial or steroid eye drops, skin and eyelid hygiene, and fish oil (Omega-3s) as found in salmon or sardines.
Often, the best method to relieve blepharitis is wetting a clean washcloth with warm water and then wringing it out until it is somewhat dry. Use the washcloth over your closed eyes for about one or two minutes.
Other people can have crusty eyes because of eye infections. Typically, this is due to pink eye, or conjunctivitis.
Conjunctivitis represents inflammation of the conjunctiva. Most of the time, pink eye means a viral infection, but it can also be caused by bacteria, allergy, or even a blocked tear duct, as in infants.
Pink eye is usually associated with crusty eyes. Treatment is focused on symptom relief and sometimes requires antibiotic eye drops. Otherwise, artificial tears, cleaning your eyelids as you would for blepharitis, and warm compresses are effective.
Tips for treating crusty eyes
First, always try to determine the reason for your crusty eyes. For example, if you have crusty eyes that are unusual for you, it may mean that you may need to be treated for an eye infection, have pink eye, or have allergies.
If you have crusty eyes and there does not seem to be a particular reason, then use some practical hygiene tips.
Always be meticulous about washing your hands before and after you touch your eyes. Be careful using harsh soaps, chemicals, or hand sanitizers since these may cause eye irritation, particularly if you don’t adequately dry your hands.
Don’t touch your eyes if you have not thoroughly washed them first. Your hands may carry germs. Also, rubbing too vigorously can cause more irritation or even infection in your eyes.
Using warm or cool clean washcloths as compresses is helpful, but don’t use them if they are too hot or too cold. Hot compresses can burn your eyelids.
Waking with a crusty build-up in the corners of your eye is common and, usually, quite normal. The crust is typically the result of a collection of fluids, mucus, blood and skin cells, and dust. However, if you gather an abundance of eye crust in one or both eyes, it may be the result of an infection or other eye problems. If that's the case, schedule an appointment with your doctor.
- Health University of Utah. Is that morning "eye gunk" normal?
- Science ABC. What Is The Crusty “Sleep” In Our Eyes When We Wake Up?
- Optical Express. What is Eye Gound?