Overnight, a yellowish crust known as “eye sleep” often forms on our eyelashes and the corners of our eyes. While some people experience more of it than others, this crust is also commonly referred to as “eye boogers” or “eye gunk,” and its medical term is “rheum.”
It’s important to note that the presence of eye sleep is completely normal. While we’re awake, blinking helps clear away tears and mucus, but during sleep, these substances accumulate in the corners of the eyes and can harden into crusts.
In addition to tears and mucus, eye sleep contains oils, dead skin cells, and bacteria along with their remains.
Dr. Rachel Clemmons, an ophthalmologist at Wills Eye Hospital in Philadelphia, explains, “The eye has several mechanisms to protect itself from infection, including antimicrobial proteins in tears and the physical barrier formed by mucus. What we see as discharge is partly evidence of your immune system successfully neutralizing harmful bacteria that could otherwise cause infections.”
According to the Cleveland Clinic, the debris on your eyes is generally harmless unless it’s associated with other conditions, such as conjunctivitis (an inflammation of the conjunctiva). In such cases, eye discharge becomes more abundant and noticeable.
Abnormal discharge may be green, sticky, excessive, or foamy. It’s often accompanied by pain, itching, redness, blurry vision, light sensitivity, swollen eyelids, or a bump on the eyelid.
Dr. Samantha Weiss, an optometrist in private practice, advises: “While some morning discharge is perfectly normal, significant changes in the amount, color, or consistency of your eye discharge should not be ignored, as they can indicate potential issues with eye health.”
Abnormal eye discharge can also be caused by various bacteria, such as Staphylococcus epidermidis, Propionibacterium species, Corynebacterium species, Streptococcus species, and other gram-negative bacteria in smaller numbers.
Infants and young children tend to have more eye discharge because their narrower tear ducts are more prone to blockages. Additionally, older adults and those with dry eyes often experience more significant buildup of eye sleep.
