A chalazion is a swollen lump on the eyelid. Chalazia arise from oil glands located near the eyelashes. If an eyelid gets inflamed, for any reason, these oil glands can get congested with very thick oil. The thick oil not only flows and functions poorly, but can also lead to more inflammation. When the patient’s immune system walls-off or isolates the inflamed oil gland tissue into a nodule, this is called a chalazion.
The most common symptom of a chalazion is a non-tender or mildly tender lump on the eyelid. The lump is usually visible, red, and noticeable to the touch. Chalazia may develop over days to weeks, sometimes at the site of a recent stye (eyelid infection). A chalazion might go away if its contents drain, either through the skin surface or onto the eyeball surface.
The oil glands in a chalazion normally help keep the eye surface moist and comfortable. When these glands malfunction, the eye can feel uncomfortable, dry, irritated, or itchy. Some patients complain of a foreign body sensation under the eyelids, and some have watery eyes. The eyelashes can also develop flakes that look like dandruff. All these problems can lead to blurry vision.