Eye Discharge Causes, Symptoms, Treatments

Written By: Susannah Lockett

Some degree of eye discharge is normal. For example, the crusty material present around the corners of the eyes and eyelids after a period of sleep is perfectly normal. Sometimes called “sleep,” this type of discharge is composed of mucus, oil, skin cells, and other cellular debris.

Eye discharge from sleep is typically dry and brittle. Although it starts as a liquid material, it evaporates during a long period of slumber. However, sleep can also appear as a sticky, gunky material rather than a dry and crusty one. Sometimes, both forms may be present together.

Either way, it’s perfectly normal and nothing to be concerned about. Simply use a clean cloth moistened with plain warm water to loosen the sleep and clean it away.

Other terms for sleep include eye boogers, mattering, eye gunk, and eye pus. This last term is highly inaccurate. The discharge in the eyes after awakening has nothing to do with pus. Pus is a thick, sticky, yellow, or greenish discharge seen in an infected wound. Sleep discharge is normal and has nothing to do with infection.

The Function of Tears

The eyes produce a mucus called mucin and an oily substance called meibum. These are secreted by separate parts of the eye and only combine in tears. Tears bathe the eyes in a constant, protective film that fights infection, nourishes cells, helps bring oxygen to the front of the eyeball, and washes away debris that may enter the eye from the air.

The eye’s cornea contains no blood vessels and relies on tears for nutrition, protection, and oxygen. Looking at the cornea from the side, you will note that it’s clear. This allows light to enter the eye and remain clear as it strikes the retina at the back of the eye. Blood vessels cannot be clear; this is why the tears are so important to the cornea.

The lack of corneal blood vessels is also why transplants of this organ are rarely rejected and seldom require long-term use of anti-rejection drugs.

Why Does Eye Discharge from Sleeping Occur?

Discharge collects in the eyes during sleep mainly because we don’t blink while we sleep. While awake, the blinking function maintains the tear film, which contains a type of mucus to help protect the eyes and wash away pathogens and debris, moving along the eyeball.

When we sleep, the lack of blinking allows mucus to collect in the corners of the eyes and sometimes along the edges of the lashes and eyelids. The medical term for this discharge is known as rheum. As long as it’s not accompanied by pain, blurry vision, sensitivity to light, and is not green or yellow in color, rheum is normal. Just clean it away gently.

Other than rheum, eye discharge isn’t normal. It may have a wide range of causes, some of them serious and some minor. The cause could be anything from a harmless but annoying allergic condition to a potentially sight-threatening eye infection or injury.

Only an eye care professional can diagnose the cause of eye discharge. Always consult your eye doctor for any kind of eye discharge other than that which is clearly just normal rheum from sleeping.

Causes of Eye Discharge

Other than normal rheum, several common conditions may cause abnormal eye discharge needing professional evaluation and treatment:


The white of the eye is called the sclera. Although you cannot readily see it, it’s covered by a thin, clear membrane called the conjunctiva. The conjunctiva also lines the inner eyelids. When it becomes inflamed or infected, this condition is called conjunctivitis or pink eye. Pink eye may be caused by viruses, bacteria, or allergies.

Symptoms of pink eye include redness of the eyeballs, itching, light sensitivity, pain, and a feeling of sand or grit in the eye or eyes. Discharge may also be present and may be clear, green, or yellow.

There are three main types of conjunctivitis, all classified according to their cause. These are allergic, bacterial, and viral.


Colored discharge is associated with infection, and this discharge may be profuse. Sometimes, this discharge is thick and sticky enough to temporarily seal the eyelid shut.

Never try to force a sealed eyelid open. Call your eye doctor immediately. You will also need treatment for the underlying condition to protect your eyes and eyesight. Both viral and bacterial conjunctivitis are always potentially contagious, so you will want to protect others around you by seeking treatment immediately.

In general, a greenish or yellowish discharge indicates a bacterial infection, while a viral one produces a clear discharge, as does conjunctivitis caused by an allergy. Allergic conjunctivitis is not contagious, but you will need an eye care professional to correctly diagnose the type of conjunctivitis you have.

Eye Infections

Other than conjunctivitis, other eye infections include acanthamoeba keratitis, fungal keratitis, and herpes virus infections. Although rare, acanthamoeba keratitis is a serious infection that can blind if left untreated.

Strongly associated with contact lens wear, this infection is often caused by poor lens hygiene, swimming, and showering with contact lenses in the eyes. The organism causing this infection may be present in tap water, but it rarely causes any problem as long as contact lenses are not in the eyes.

Discharge from eye infections may range from clear to green or yellow or may not be present at all. Only an eye care professional can diagnose and treat any possible eye infection. If you wear contacts, follow your doctor’s lens care instructions.

Never take shortcuts or make up your own care routine. Sight-threatening infections may occur if you do this. Never use tap water or saliva to care for or insert contacts into your eyes. Use the solutions recommended by your eye care professional. Never wear expired or damaged contact lenses, either.


This is typically a chronic and stubborn inflammation of the eyelids. Symptoms may vary, including a foamy eye discharge, eyelid redness and crusting, irritation, itching, and green or yellow discharge. Blepharitis may also occur in pets. Whenever it occurs, it requires expert management by an eye care professional.


The meibomian glands at the base of the eye produce the oil component of tears. When one of these tiny glands becomes blocked, it may also become inflamed and infected, producing a hard, red, painful lump known as a stye. This is similar to an infected pimple on the skin.

A stye may also cause some discharge and eyelid crusting. You may find relief by applying a warm, clean compress to the area, which may encourage the stye to resolve itself.

A stye will generally clear on its own, but if it does not after a couple of days, seek treatment from your eye doctor right away. Never try to pop a stye.

Dry Eye

When the meibomian glands malfunction, they may fail to produce enough oil for tears. When this occurs, the tears don’t moisturize the eyeball sufficiently, and a feeling of dryness and grit in the eyes may result. The eye may try to compensate by increasing tear production, which may look like a clear discharge.

Because these increased tears still don’t contain enough oil, the dry eye condition will persist. Dry eye is a complex but generally treatable eye condition. Your eye care professional will determine the cause of your dry eye and then prescribe the correct treatment.

Treatment of Eye Discharge

This will depend on the cause, but bacterial eye infections may be treated with antibiotic eye drops, ointments, oral antibiotics, or a combination of the three. Certain viral eye infections may respond to antiviral eye drops or ointments. Allergic eye discharge may be treated with antihistamines, certain steroid drops, or decongestants.

Only your eye care professional can prescribe the correct treatment for your eye discharge. In particular, steroids like prednisone should only be used for short periods under direct medical supervision.

A Note to Parents

Babies are commonly born with blocked tear ducts. This may cause a clear, profuse, watery discharge to appear in the baby’s eyes shortly after birth. There may also be some sticky crusting in the eyelashes.

The condition is harmless and will clear in time, but you can ask your child’s pediatrician about gentle tear duct massages to help unblock the baby’s tear ducts faster.

Find an Eye Doctor Near You

Adults and children should receive yearly eye exams to evaluate eye health and catch any problems early. Our list of top-rated eye doctors is designed to quickly and easily help you find a highly qualified eye care professional in your area.

Establishing a relationship with an eye doctor who knows you is important. We’ve made it easier than ever to find a great eye doctor in your neighborhood.

Published on: July 3, 2022
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