Sleep crust is an eye discharge and is referred to as rheum in medical terms. It is the crusty material that forms in the corners of the eye during sleep. 

Sleep crust is made of tears, oil, mucus, exfoliated skin cells and other debris that collects in the corner of the eyes during sleep. The eye discharge may be dry and crusty or wet and sticky. It depends on the evaporation of the fluid in the discharge. 

The purpose of the eye discharge is usually to protect the eyes. It removes waste products and other harmful material from the front surface of the eyes and the tear film.

The eyes are always producing tears and mucus during the day for normal functioning and protection. When a person blinks, the excess fluid including irritants and debris such as dirt, dust and stray eyelashes are flushed out.

During sleep, the eyes continue to produce mucus and tears. Since one is not blinking, the eye discharge accumulates in the corners of the eyes and eyelashes.

Also Known As

  • Eye gunk
  • Eye pus
  • Eye mattering
  • Eye boogers
  • Rheum
  • Sleepy dust
  • Goopy eyes

Causes and Risk Factors

Eye discharge is a natural function of the eyes. A change in color, frequency, quality, amount and consistency, might indicate a disease or infection.
Common eye conditions that cause abnormal discharge include:

  • Blepharitis
  • Dacryocystitis or blocked tear duct
  • Dry eye syndrome
  • Bacterial conjunctivitis
  • Allergic conjunctivitis
  • Stye
  • Eye herpes
  • Fungal keratitis
  • Eye injury
  • Corneal ulcer

Risk factors include:

  • Unhygienic environment 
  • Use of contact lens
  • Malfunctioning eyelid oil glands
  • Hazardous work and sports
  • Old and outdated eye makeup
  • Seborrheic dermatitis or dandruff of the scalp and eyebrows  
  • Eyelash lice or mites

Signs & Symptoms

Where the eye discharge has changed color (often yellow or green), or there is an excessive or thick discharge, it could be a sign of a problem.
Other symptoms could include:

  • Eye pain
  • A red eye
  • Itching eyes
  • Increased sensitivity to light
  • Inflammation
  • Blurred vision
  • Fever
  • The sensation of a foreign body in the eye
  • Dry eyes


The eye care professional will take the patient’s medical history, symptoms and conduct an eye examination. It may include:

  • External and anterior segment examination 
  • Assessment of the tears to look for abnormalities
  • Slit lamp examination 
  • Dilated fundus exam 
  • Intraocular pressure exam
  • Fluorescein eye stain eye test


Treatment is focused on the cause of the abnormal eye discharge.

Medical Treatment

The eye doctor may prescribe:

  • Artificial tears for dry eyes
  • Antibiotics for an eye infection
  • Antiviral ointments and eye drops for a viral infection
  • Antifungal medicines, including oral medication and eye drops for a fungal infection
  • Antihistamine eye drops and decongestants for eye allergies

Surgical Treatment

Where there is an embedded or attached foreign body, the eye surgeon will use needles and other specialized tools to extract it.

Home Care

Warm compresses placed over the eyes may relieve symptoms of general eye discomfort and itching. It also removes eye gunk.

The best way to separate eyelids that are stuck together is to wet a washcloth in hot water.  Place it over the eyes for a few minutes, then wipe out the sleep crust.

Prognosis/Long-term outlook

Sleep crust is no cause for concern. However, if one notices an abnormal eye discharge, it is important to see an eye doctor without delay.  

It could be a sign of an eye disease. Some diseases like blepharitis, herpes keratitis and fungal keratitis may have severe visual consequences. Others such as bacterial conjunctivitis are very contagious and can spread to the other eye and even to other people.

Prevention/Follow Up

Simple tips to prevent or manage eye discharge include:

  • Avoid touching the eyes to prevent the onset or spread of an eye infection.
  • Using a clean, warm moist washcloth to remove sleep crust instead of fingers. 
  • Washing hands often, particularly if one has a contagious pink eye.
  • People who use contact lenses should always respect the lens care regimen.
  • Discarding any contaminated cosmetics like mascara and eyeliner, if one has an eye infection.
  • Maintaining good hygiene at both personal and environmental levels
  • Using protective gear for hazardous work, sports and other outdoor activities