8 Reasons Why You Have Crusty Eyes, and What To Do About It

Eye crust forms when mucus, oils, and debris accumulate, often during sleep. This buildup is a normal part of the eye’s maintenance process. However, crusty eyes can also indicate underlying issues like eye infections or allergies.

Understanding the causes and characteristics of this phenomenon can help identify when it is normal and when it might be a sign of a more serious problem.

Eye crust is a hard or sticky discharge visible on the lash line or in the corners of the eyes. The consistency can vary. For some people, it may appear yellow and feel hard. Others may have a clear and sticky substance, while others will notice a thin and watery consistency.

There are several causes of crusty eyes, which range from eye infections to allergies. Here are some of the more common causes:

Sleep

Crusty eyes are commonly called “sleep crust.” During sleep, the eyes are at rest and do not blink, causing eye discharge to pool in the corners of the eyes and along the lash lines. This causes a harmless crust to form, which is noticeable upon waking. This crust may appear hard, crusty, sticky, or wet. 

Blocked Tear Duct

Blocked tear ducts—also called nasolacrimal duct obstruction (NLDO) or dacryostenosis—are another common cause of crusty eyes. Blocked tear ducts are a common eye condition in newborn babies. However, it can affect people of all ages.

It begins when normal tear production starts. This causes excessive tearing, redness, and crusty eye discharge, which can appear sticky and yellowish-green.

Allergic Conjunctivitis

The conjunctiva is a thin layer of tissue that covers the whites of your eyes and the inside of your eyelids. When the conjunctiva becomes inflamed or swollen from allergy-causing substances, such as pet dander, mold, and dust mites, allergic conjunctivitis can result.

Allergic conjunctivitis affects up to 40% of the population and is characterized by intense itching, tearing, puffy eyelids, and clear, watery eye discharge with visible crusting.

Dry Eye

Dry eye is a common eye condition affecting nearly 16 million people in the United States. It can cause crusty strings of mucus in or around the eyes.

You may also feel burning or stinging, and vision can become blurry. Other symptoms include a scratchy feeling in the eye and eye redness. Wearing contact lenses may be painful with dry eyes.

Bacterial Conjunctivitis (Pink Eye)

The main symptom of bacterial conjunctivitis, also known as pink eye, is redness in the eye. Other symptoms may include discharge, itching, and pain. Crusts on the eye, increased tearing, light sensitivity, and a feeling of grittiness in the eye can also occur.

Blepharitis

Blepharitis is a noncontagious eye condition that causes the eyelids to become inflamed, red, and itchy. It causes crusty flakes on the eyelashes and may make the eyes feel dry.

The condition can be acute (short-term) or chronic (long-lasting), but it usually requires long-term management and daily cleansing of the eyelids to keep the condition in check.

Less Common Causes

Some less common causes of crusty eyes include keratitis (corneal ulcers) and styes.

Keratisis sores, which form on the cornea (the clear protective outer layer of the eye), are usually caused by an eye infection. However, eye disorders such as severe dry eye can also cause it. Symptoms include pus, crusty discharge, light sensitivity, redness, severe pain, and tearing.

A stye is a painful red bump that forms on the edge of the eyelid at the base of the eyelashes. Styes can cause crustiness, tearing, swelling, and a small spot filled with pus at the center of the bump.

While crusty eyes can be normal (in the case of sleep crust), some eye crust may indicate an infection or eye condition that needs treatment. See a healthcare provider, such as an ophthalmologist (eye specialist), if you experience any of the following symptoms:

• Blurred vision
• Light sensitivity
• Excess eye discharge
• Eye discharge that is thick, greenish-yellow, or resembles pus
• Sticky lids
• Redness
• Increased eye swelling
• Eye pain
• Decreased vision

A healthcare provider will examine the eye to determine the cause of your crusty eyes. They may also perform a vision test and check how your pupils react to light to help make an accurate diagnosis.

Self-care remedies can help keep your eyes clean and clear of discharge. Try the following at-home treatments to treat crusty eyes:

• Lay a warm compress or washcloth on your eyelids and eyelashes and gently rub the area to help soften eye crusts
• Remove recurring eye crusts by washing the eyelids daily with baby shampoo and water applied to a washcloth

If underlying allergies or infections are to blame, see a healthcare provider. Prescription eye drops can be prescribed for certain eye conditions and allergies.

Crusty eyes can be uncomfortable, but proper preventative care can help. To prevent and reduce your chances of getting crusty eyes, try the following tips:

• Regularly wash your hands with soap and water to prevent bacterial conjunctivitis and other eye infections
• Wash your eyelids daily with water and baby shampoo using a soft washcloth or cotton swab, especially if you are prone to blepharitis or recurring crusty eyes
• Use lubricating eye drops to keep your eyes moist if you have dry eyes
• Try antihistamine eye drops to help relieve allergy symptoms

Crusty eyes may be caused by sleep, allergic conjunctivitis, blocked tear ducts, and blepharitis. You can treat and prevent crusty eyes at home by cleansing eyelids daily and applying warm compresses.

If you experience worsening or persistent symptoms such as excess discharge, blurred vision, light sensitivity, redness, pain, or decreased vision, see a healthcare provider for diagnosis and care.

Crusty eyes can be unsightly and irritating, but there are ways to manage and treat the debris and keep your eyes clean and healthy.